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Comparative effectiveness research designs: an analysis of terms and coverage in Medical Subject Headings (MeSH) and Emtree.

INTRODUCTION

The emergent field of comparative effectiveness research (CER) ([double dagger]) is beset by differences in language among stakeholders. These include methodologists in organizations that promote CER, scientists who generate original data or synthesize secondary data, panels of experts who rely on extant research to design guidelines for best practice, and policymakers who identify and prioritize future research needs. For health sciences librarians who regularly support this panoply of stakeholders, it is necessary to know about differences in order to interpret service requests. For example, the following terms are used inconsistently: CER, evidence-based medicine (EBM), and health technology assessment (HTA); randomization and random sampling; efficacy and effectiveness.

Recently, the MLA News published two accessible reports to introduce librarians to CER in which the authors compare CER and EBM [2, 3]. A more thorough essay comparing CER, EBM, and HTA along several dimensions appears in The Milbank Quarterly [4], with some discussion of semantic differences between North America and Europe. The authors of another paper discussing infrastructure needs and capacity for conducting CER report that while capacity is adequate, the "majority of researchers are trained in either observational study methods or randomized trials, but rarely both" [5]. Thus, a lack of awareness of major approaches to research likely exacerbates the confusion in language. Note that in this paper, we use the term language to mean natural as opposed to formal language, with a focus on the use of phrases to communicate concepts for study designs. Jurafsky and Martin's text explains the disctinction [6]. Several authors provide background papers on the structure of scientific language, sub-languages, and epistemological differences among disciplines [7-9].

An important aspect of CER is the focus on the generalizability of findings to diverse populations of real interest. Broadly, CER is concerned with answering questions regarding effectiveness rather than efficacy of interventions, which has implications for the usefulness of various study designs. Nonrandomized (NR) or observational studies, rather than randomized controlled trials (RCTs), may better answer effectiveness questions, even though well-known threats to validity exist for the former [10]. For example, consider that a well-conducted RCT ensures the statistical equivalence of groups via randomization (random assignment of treatments to experimental units or vice versa) prior to treatment and that finding a treatment effect is therefore likely to be reproducible under the same experimental conditions. However, the design of an RCT promotes internal validity at the expense of external validity (generalizability) when the investigators cannot randomly sample "units," such as patients. In contrast, researchers who conduct an NR study might randomly sample participants from populations of interest. Random sampling, if done well, as opposed to random assignment ensures that study groups will resemble the populations of interest. This is a major reason for recognizing the value of evidence derived from NR studies. In the best of worlds, a CER question would be answered by both RCTs and NR studies. This is why systematic reviewers who synthesize biomedical evidence look for both kinds of studies.

Unfortunately, consensus does not exist regarding how best to describe NR studies common to CER. According to the Cochrane Non-Randomised Studies Methods Group, both investigators and indexers inconsistently describe study designs [11]. Challenges arise for expert searchers, indexers, and methodologists due to the hodgepodge of terms that stakeholders use within and across disciplines. This problem is well known, and groups around the world have issued statements regarding standards for reporting studies and their designs. To improve the value of medical research, an international initiative known as the EQUATOR Network [12] maintains a library of reporting guidelines by study type, such as STAndards for the Reporting of Diagnostic Accuracy Studies (STARD) for diagnostic accuracy studies [13], Consolidated Criteria for Reporting Qualitative Research (COREQ) [14], and STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) [15]. In general, guidelines suggest that authors name their study design in the title or abstract and use a common term, but names are not standardized. Thus, inconsistent indexing and varying stakeholder language, as well as multiple reporting standards lead to serious retrieval challenges for health sciences librarians.

In this study, we investigated whether methodologists in several highly regarded CER organizations share a terminology for study designs and to what extent. By terminology, we mean a set of mostly phrases, which is consistent with International Organization for Standardization (ISO) 1087 "Terminology-Vocabulary Standard," described by Hammond and Cimino [16]. To compare organizational terminologies, we culled design terms and terms for related concepts from relevant documents. We then built a CER design terminology based on the documents we identified to evaluate whether and how terms for study designs used by experts correspond to terms in Medical Subject Headings (MeSH) [17] and Emtree [18], the controlled vocabularies for MEDLINE and Embase, respectively. To support librarians, we developed a crosswalk between MeSH and Emtree with suggestions for queries when design terms partially map to broad controlled terms or fail to map. We also explored whether scientists use CER design terms to describe their own studies.

METHODS

Data sources

To ensure relevancy, we elected to work with classification algorithms from respected CER organizations. Further, to ensure validity, we selected algorithms already vetted by methodologists. We therefore chose algorithms developed by organizations identified in two recent methods studies funded by the Agency for Healthcare Research and Quality (AHRQ) [19, 20]. The organizations and data sources included:

1. University of Alberta Evidence-based Practice Center (Alberta). Developing and Testing a Tool for the Classification of Study Designs in Systematic Reviews of Interventions and Exposures: Appendix G. Round Two Algorithm and Glossary [19].

2. AHRQ. Framework for Considering Study Designs for Future Research Needs: Table 1: Study design terms; Appendix A: Taxonomy for Study Designs; Table A-2: Terms Associated with Study Designs [20]. This draft report was submitted for public comment September 2011.

3. Cochrane Non-Randomised Studies Methods Group (Cochrane). Design Algorithm for Studies of Health Care Interventions; appears in Appendix H of the Alberta report [19]. Additionally, Box 13.1.a: Some Types of NRS [non-randomized studies] Design Used for Evaluating the Effects of Interventions; Table 13.2.a: List of Study Design Features (studies with allocation to interventions at the individual level); Table 13.2b: List of Study Design Features (studies with allocation to interventions at the group level) [11].

4. Academy of Nutrition and Dietetics, formerly known as the American Dietetic Association (ADA). Evidence Analysis Manual: Appendix 5: Algorithm for Classifying Research; Appendix 6: Glossary of Terms Related to Research Design [21].

5. Research Triangle Institute International-University of North Carolina Evidence-based Practice Center (RTI). Design Algorithm for Studies of Health Care Interventions; appears in the Alberta report, Appendix H [19].

We extracted terms from the selected resources and augmented subsequent lists with designs mentioned in corresponding glossaries, tables, and appendixes. We refer to the resultant lists of terms as local terminologies (LTs) throughout this paper.

In developing the Alberta algorithm, a steering committee with members from AHRQ and AHRQ-funded evidence-based practice centers (EPCs) identified thirty-one organizations and experts. They asked respondents to return classification tools or systems to "ensure that we have a broad spectrum" (Letter of Request to Identify Study Design Classification Tools, Appendix C; see also Appendix B for a list of contacts [19]). The identified organizations included all fifteen of the AHRQ-funded EPCs and seven other organizations, such as the Cochrane Collaboration, the Campbell Collaboration, and the National Health Service (NHS) of the United Kingdom. Additionally, nine anonymous experts were contacted. Eleven respondents returned twenty-three tools, algorithms, guidelines, or instruments for classification. Ten were selected for further analysis. Members of the steering committee independently rated the selected tools and identified the Cochrane algorithm as most suitable for further development. The ADA and RTI algorithms were rated second and third, respectively.

The Alberta algorithm is the basis for a framework currently being developed by AHRQ to promote a standard taxonomy for considering the suitability of various designs in carrying out future research. Data sources in the AHRQ report include designs that vary somewhat orthographically from the Alberta report, along with additional terms (e.g., systematic review, modeling, and meta-analysis of individual participant data).

Development of a new comparative effectiveness research (CER) design terminology

We manually extracted terms from the data sources just described. For example, if the source was a classification algorithm structured as a decision tree, we extracted the design term and any examples or synonyms displayed at the end of each path. If the source was a glossary, we extracted each term along with any examples mentioned in its description. If the source was a table, we extracted terms in the cells or, if applicable, from the footer defining design acronyms used as column names.

We pooled terms from all five LTs, deleted duplicates, and converted to lower case. We treated as equivalent orthographic variations--such as randomized (US spelling) and randomised (British spelling); meta-analysis, metaanalysis, and meta analysis; and before-after and before-and-after. Similarly, we considered as equivalent singular and plural words, such as study and studies, and acronyms for corresponding terms, such as RCT for randomized controlled trial and IPD for individual patient data.

After term extraction, augmentation, and processing in the manner described, the union of terms occurring in one or more LTs defined the new CER design terminology. Additionally, the intersection of terms occurring in all five LTs defined the core set of design terms.

Match types and coverage

To evaluate coverage, we searched for CER design terms in MeSH and Emtree. We recorded the type of match per term as exact, partial, orno match; coverage was defined by the distribution over match type. In MeSH, if a CER term or any of its variants directly mapped to a main heading or entry term, the match was exact; if part of the term mapped to a broader or related term or to a substring in a scope note, the match was partial; otherwise, "no match" was recorded. Mapping procedures in Emtree were modified somewhat but were quite similar to those in MeSH.

Search for CER design terms in Medical Subject Headings (MeSH) and Emtree

We used the US National Library of Medicine (NLM) MeSH browser [22] to search for terms in a stepwise manner. In each step, we used a different combination of browser settings but otherwise followed the same search strategy:

a. We selected the settings "All of the Above" (Main Headings, Qualifiers, and Supplementary Concepts) plus "Find Exact Term." If no hit was returned, we reduced the design phrase by a word or stemmed by shortening words to a base form (e.g., nonrandomized controlled trial became nonrandomized controlled, nonrandomized, nonrandom, etc.).

b. If no hit was returned in step (a), we selected "Find Terms with ALL Fragments" and searched for strings of text as in the first step.

c. If no hit was returned in step (b), we selected "Search as text words in Annotation & Scope Note" plus "Find Terms with ALL Fragments" and again searched for a similar sequence of text strings.

We also searched Emtree in Embase [18], a subscription database. We navigated to the "Find Term" tab and modified terms in a stepwise manner as in MeSH, first searching for exact matches. On occasion, searching for study or trial was helpful, as it led to a variant form that we considered equivalent (e.g., validity study does not directly map to validation study, but appears under study).

Crosswalk between MeSH and Emtree

We created a crosswalk between MeSH and Emtree for CER design terms by recording the controlled terms to which they exactly or partially mapped. For partial and no matches, we recorded whether terms were negated or detailed, if appropriate. A negated term includes at least one word or phrase that is counter to or is in opposition to an affirmed word or phrase in another design term. For example, interrupted time series without comparison group is a negated term because it is counter to an interrupted time series with comparison group. Specifically, without comparison group negates with comparison group. Both design terms are detailed because they are multiword phrases with several modifiers, including interrupted, time, and comparison.

In the crosswalk, we offered suggestions regarding potential alternatives or query expansions for some design terms.

The language of scientists and CER experts To explore whether scientists use the terms for designs and related concepts as expressed by experts in CER organizations, we used quoted strings of terms and variants and restricted our searches to titles and abstracts. Because Embase regularly adds MEDLINE records [23], we could search records from both databases via Embase, which ensured comparability of searches.

To count the number of hits per CER term by database, we compared hits from two searches. In the first, we searched de-duplicated records originating in either database using <design term>:ab,ti. In the second, we restricted the search to records from Embase using <design term>:ab,ti NOT [medline]/lim AND [embase]/lim. To find the number of hits in MEDLINE, we subtracted the count for the second search from the first. Here is a sample query:

'before-after study':ab,ti OR 'before-after studies':ab,ti OR 'before-after design':ab,ti OR 'before-after designs':ab,ti OR 'before-after trial':ab,ti OR 'before-after trials':ab,ti OR 'before-and-after study':ab,ti OR 'before-and-after studies': ab,ti OR 'before-and-after design':ab,ti OR 'before-and-after designs':ab,ti OR 'before-and-after trial':ab,ti OR 'before-and-after trials':ab,ti NOT [medline]/lim AND [embase]/lim

Statistical analyses

We used Excel 2003 and 2010 [24, 25], as well as IBM SPSS version 20 [26], for statistical analyses of term distributions, computation of pairwise LT overlap and overlap with the CER design terminology, evaluation of coverage, and comparison of hits for queries. By overlap, we mean the percentage of shared terms between LTs or between an LT and the CER design terminology.

RESULTS

Terminologies

The augmented LTs varied in length: Alberta (n = 33 terms), AHRQ (n = 39), Cochrane (n = 32), ADA (n = 36), and RTI (n = 25). The CER design terminology (n = 78) derived from terms that occurred in 1 or more LTs mostly consisted of terms for primary study designs and a few terms useful for evaluating evidence, such as opinion paper and systematic review (Table 1). About half the terms (47.44%, 37/78) appeared in just 1 LT. A few terms (8.97%, 7/78) were common to all LTs (Figure 1). These included before-after study, case-control study, case series, cross-sectional study, prospective cohort study, retrospective cohort study, and randomized controlled trial.

Alberta had the most in common with the other terminologies (mean pairwise overlap = 48.77%, 24 shared terms on average); RTI had the least in common (25.65%, 12 shared terms on average) (Table 2). The overlap between pairs of LTs ranged from 22.64% (12 shared terms) for AHRQ and RTI to 75.61% (31 shared terms) for Alberta and AHRQ (Table 2). The overlap of LTs with the new CER design terminology ranged from 32.05% (25/78) for RTI to 50.00% (39/78) for AHRQ (Table 3).

Coverage and characteristics of match type

Patterns of coverage in MeSH and Emtree are displayed in Table 4 and Figure 2. Coverage as defined by the distribution over match type was similar; the association was positive and statistically significant (Goodman Kruskal gamma = 0.581, P = 0.002). Gamma is a nonparametric measure suitable for testing the bivariate association between ordinal variables. It can be interpreted as a correlation coefficient, as it falls between -1 and +1.

Match type per term is displayed in Table 5 (online only). The terms to which CER design terms most often mapped were similar in both vocabularies. In MeSH, they were randomized controlled trial, controlled clinical trial, longitudinal studies, cohort studies, and clinical trial. In Emtree, they were randomized controlled trial, controlled study, time series analysis, and cohort analysis.

Frequent partial mapping indicated a broad or related MeSH or Emtree term. For example, the following CER terms mapped to the MeSH term randomized controlled trial: cluster randomized controlled trial, cluster randomized trial, group randomized trial, open-label randomized controlled trial, randomized trial, and single-blinded randomized controlled trial. In Emtree, the terms were the same with the exception of open-label randomized controlled trial, which mapped to open study.

We labeled CER design terms as detailed relative to MeSH and Emtree if they consisted of more than 3 words, ignoring prepositions and hyphens (23.08%, 18/78). Almost all of the MeSH terms and entry terms, and most of the Emtree terms and synonyms to which CER terms mapped were at most 3 words long. Examples of detailed CER terms included cluster quasi-randomized controlled trial and meta-analysis of individual participant data.

Several terms (14.10%, 11/78) involved negation, such as cluster nonrandomized controlled trial, interrupted time series without comparison group, nonrandomized crossover trial, and uncontrolled longitudinal study.

For exact matches in 1 or both controlled vocabularies (n = 29), 1 term was detailed (3.45%, 1/29) and 1 negated (3.45%, 1/29): nested case-control study and non-experimental study, respectively. Emtree covered more terms exactly than MeSH (26 Emtree vs. 15 MeSH).

For partial matches in 1 or both controlled vocabularies (n = 55), 18 terms were detailed (32.73%, 18/55) and 10 negated (18.18%, 10/55). MeSH covered more terms partially than Emtree (49 MeSH vs. 45 Emtree). Sixteen terms partially mapped to a MeSH term because of a matching substring in the scope note. For example, trend study mapped to the MeSH term sentinel surveillance because the scope note included the following excerpt: "the study of disease rates in a specific cohort, geographic area, population subgroup, etc. to estimate trends [emphasis added]."

For terms not matched in 1 or both controlled vocabularies (n = 15), 13.33% (2/15) were negated: noncomparative study and non-experimental study. (Note that while non-experimental study failed to map in MeSH, it exactly mapped to a synonym for observational study in Emtree.) No unmatched term was detailed. MeSH had twice as many "no matches" as Emtree (14 MeSH vs. 7 Emtree). Both controlled vocabularies failed to cover before-after study (including variants), which is a core term appearing in all 5 LTs. Checking whether unmapped terms appeared in any of the Unified Medical Language System (UMLS) resources [27], we found that 20% (3/15) mapped to terms in the National Cancer Institute (NCI) Thesaurus [28], including community trial (C1516736), factorial study (C2826344), and parallel study (C2826345).

CER design queries

The average number of hits for CER design queries restricted to titles and abstracts varied with the record source and type of match.

The median (MDN) number of MEDLINE records retrieved in Embase was 1,090 (range: 0 to 222,804); the MDN number of Embase records was 380 (range: 0 to 89,807). Case report yielded the most hits for both MEDLINE and Embase.

Average hits by type of match were: MeSH exact (MDN = 37,750; range: 960 to 222,804), partial (MDN = 735; range: 0 to 114,303), or no match (MDN = 590; range: 11 to 11,915); Emtree exact (MDN = 9617; range: 54 to 89,807), partial (MDN = 199; range: 0 to 22,584), and no match (MDN = 152; range: 9 to 432).

Based on nonparametric independent-samples median tests (MTs), the average hits varied significantly across type of match for MeSH (MT = 14.022, df = 2, P < 0.001) and Emtree (MT = 19.789, df = 2, P < 0.000). Pairwise differences in hits were significant for the exact versus partial category comparison (MeSH MT = 14.716, P < 0.000; Emtree MT = 16.258, P < 0.000) and the exact versus no match category (MeSH MT = 12.523, P < 0.001; Emtree MT = 8.362, P < 0.011). Differences were statistically nonsignificant for the partial versus no match comparison in both MeSH and Emtree. P values were adjusted for the number of comparisons.

DISCUSSION

Terminologies

With the exception of the AHRQ and Alberta LTs, organizational terminologies varied quite a bit as measured by pairwise overlap and overlap with the new CER design terminology. The reason for this exception is that AHRQ is developing a taxonomy for study designs that builds on the Alberta classification tool. However, the overlap was not perfect because we augmented the basic set of terms that the 2 organizations share with terms from supplementary documents. Note that augmenting term lists was useful because we were not evaluating extant terminologies per se, but were interested in using documents vetted by methodologists to analyze differences in language. Thus, the mean pairwise overlap of 36% for the augmented LTs and the mean overlap of 42% with the CER design terminology substantiated what we had expected: that language varies by organization even when the domain is ostensibly the same.

To explore coverage of designs and related concepts in MeSH and Emtree, we developed a terminology that consists of terms used by organizations dedicated to promoting CER, especially systematic reviews of medical evidence. Just seven terms were common to all five organizations, and even this core set of shared terms was inconsistently covered in the controlled vocabularies. For example, the core terms case-control study, cross-sectional study, and randomized controlled trial exactly mapped to controlled terms in both MeSH and Emtree; whereas, case series exactly mapped in Emtree and partially in MeSH; prospective cohort study and retrospective cohort study partially mapped in both; and before-after study failed to map in either. This inconsistent coverage of core terms suggests that CER organizational language does not correspond well with indexing for designs.

Regarding the full set of terms for designs and related concepts in our terminology, most either partially mapped or failed to map to broad or related controlled terms. In some cases, the controlled terms were not for study designs per se, but research domains. For example, analytic study mapped to analytical research and descriptive study to descriptive research in Emtree. Interestingly, while the core term randomized controlled trial exactly mapped in MeSH and Emtree, the counter term nonrandomized controlled trial appearing in the full set did not, even though the latter is a common design. In general, negated terms rarely mapped exactly, with the exception of non-experimental study in Emtree.

Because CER is an emerging discipline, resources are being developed at the regional and federal level to help expert searchers. For example, the University of Pittsburgh Health Sciences Library System, a Regional Medical Library for the Middle Atlantic Region of the National Network of Libraries of Medicine, developed MedTerm Search Assist [29]. This tool promotes sharing of biomedical terms and comprehensive search strategies among librarians. One can browse for comparative effectiveness research to find keywords, MeSH terms, and a search filter. Currently, the fields include a few design terms, such as cluster randomized trial and pragmatic clinical trial.

At the federal level, NLM resources are available online by navigating to Comparative Effectiveness Research from Topic-Specific Queries on the PubMed home page [30]. For example, the complex query for Observational Studies consists of several blocks: <study designs> AND <comparative terms> AND <common CER topics>. Ignoring spelling variants, most of the terms in the study design block exactly or partially match MeSH terms that we found, with the exception of practice guidelines as topic, matched-pair analysis, and multicenter study. However, quite a few of the relevant designs identified in this study do not appear in the PubMed query.

It is worth noting that the PubMed query for Observational Studies includes terms for retrieving registry studies [31], terms which do not appear in the documents we mined for this analytical study. However, neither the PubMed query nor our CER design terminology has a term for hospital-based case control studies, a design covered in Emtree. Both registry and hospital-based case control studies are increasingly important in CER, partly because electronic medical records facilitate data reuse within health care systems and research across institutions.

Crosswalk

The CER design terminology and its crosswalk (Table 5, online only) may be useful for expert searchers who need to search MEDLINE and/or Embase. They could consult the crosswalk when developing queries for users who want studies in the CER domain, especially studies with designs that methodologists classify with negated or detailed phrases or terms such as head-to-head study and pragmatic trial important in CER. The latter pair failed to map in MeSH and Emtree.

Throughout Table 5, librarians will find suggestions for alternative terms or query expansions. Because this is a first effort, librarians should be alert to the potential for false positives. For example, focus group exactly mapped to information processing in Emtree because it occurs in a long list of synonyms, and reliability study partially mapped to validation studies in MeSH because reliability is mentioned in the scope note.

In general, MeSH terms for <design> as topic should be avoided, as this heading is usually not assigned to primary studies. However, at times it may be necessary, for example, pre-post study mapped to evaluation studies as topic.

Methodologists used a variety of terms to classify studies involving time, including several versions of before-after study modified by controlled or cohort, time series modified by interrupted and with comparison group or without comparison group, historically controlled trial, nonconcurrent cohort study, pre-post study, several terms modified by prospective or retrospective, and uncontrolled longitudinal study. All of these are not well indexed.

In sum, queries for designs with partially mapped terms could consist of free text for modifiers such as nonrandomized or prospective added to broader or related controlled terms, if they exist. Queries for designs with unmapped terms require free text by necessity.

Scientists' language

When we considered whether scientists use CER design terms, some striking discrepancies emerged. For example, scientists commonly used terms not well indexed in MeSH or Emtree, such as before-and-after study (1,854 total hits in Embase), descriptive study (16,408 hits), diagnostic study (4,849 hits), prospective cohort study (19,096 hits), and retrospective cohort study (14,798 hits).

On the other hand, scientists rarely used detailed terms, such as cluster nonrandomized controlled trial, cohort before-and-after study, and interrupted time series with comparison group. They were much more likely to describe in various parts of the titles and abstracts how their studies were carried out, effectively splitting up the concepts in detailed terms. For example, searching for "cohort" [tiab] AND "before-and-after" [tiab] in MEDLINE yielded 2,804 hits; whereas, searching for the CER design string "cohort before-and-after study [tiab] yielded 0 hits (24 May 2012). As an aside, searching for just "cohort [tiab] returned 190,261 hits, which was counter to Eldredge's finding that "authors rarely use the label 'cohort' when describing their methods" (p. 85) [32]. His comment together with the results of this simple MEDLINE query for cohort point to presumed differences in the sublanguages of librarianship and biomedicine, although this may be changing.

Limitations and future research

To improve upon the representativeness of the CER design terminology, additional documents could be mined, such as the AHRQ and Cochrane glossaries [33, 34], which are broader than the documents we used in this study. To be globally representative, documents from major international centers, such as the NHS National Institute for Health and Clinical Excellence in the United Kingdom, could be of use.

In our exploration of scientists' language, we were unable to infer detailed study designs by simple string matching of CER phrases in titles and abstracts. Thus, to improve our approach, semantic analysis [6] of texts written by scientists could be worthwhile.

The crosswalk in Table 5 (online only) could be further developed by librarians, paying attention to the potential for false positives given their users' needs and changes in indexing. An obvious extension would be to add other controlled vocabularies for databases that librarians regularly search, such as PsycINFO. Additionally, more terms such as comment or letter for "NOTing out irrelevant content" should be added, as these can improve precision for exhaustive searches [35]. Although it was not our intention to develop a search filter, our design terminology and its crosswalk could be of use to librarians and trials search coordinators who support systematic reviewers and other comparative effectiveness researchers.

CONCLUSION

In this study, we have demonstrated that the degree to which methodologists in CER organizations share a terminology for designs varies considerably. Further, we have shown that coverage of design terms and related concepts is similar in MeSH and Emtree and that the majority of terms partially map or fail to map to controlled terms. This poses challenges for librarians who support users in various CER communities. Finally, exhaustive searches require free text for concepts appearing in detailed design phrases because scientists split up terms in their titles and abstracts.

Highlights

* Local terminologies for study designs vary across organizations that promote comparative effectiveness research (CER).

* Coverage of design terms common to CER is similar in Medical Subject Headings (MeSH) and Emtree. Most negated or detailed terms partially map or fail to map to controlled terms.

* A crosswalk (online only) between MeSH and Emtree provides suggestions for alternative terms and query expansions.

Implications

* Librarians and trials search coordinators who support various CER stakeholder communities can consult the crosswalk for ideas when developing the design block for their search filters.

* Because scientists appear to split up concepts in detailed design phrases used for classification by methodologists, and modifiers and basic design names can occur in different places in their titles and abstracts, librarians may need to write queries that use free text for pieces of a design phrase along with controlled terms, if they exist.

* The crosswalk developed in this study could also be useful for expert searchers when designing filters requiring terms for designs in domains other than CER.

DOI: http://dx.doi.org/10.3163/1536-5050.101.2.004

Received June 2012; accepted September 2012

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[25.] Microsoft Office Excel 2010 [computer program]. Redmond, WA.

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[30.] US National Library of Medicine. NLM resources for informing comparative effectiveness [Internet]. The Library; 2009 [rev. 21 Dec 2010; cited 24 May 2012]. <http://www .nlm.nih.gov/nichsr/cer/cerqueries.html>.

[31.] AHRQ Agency for Healthcare Research and Quality. Registries for evaluating patient outcomes: a user's guide [Internet]. 2nd ed. The Agency [rev. 3 Mar 2010; cited 27 May 2012]. <http://www.effectivehealthcare.ahrq.gov/index.cfm/ search-for-guides-reviews-and-reports/?pageaction = display product&productid = 401>.

[32.] Eldredge JD. Inventory of research methods for librarianship and informatics. J Med Lib Assoc. 2004 Jan; 92(1):83-90.

[33.] Agency for Healthcare Research and Quality. Glossary of terms [Internet]. The Agency [cited 10 May 2012]. <http:// www.effectivehealthcare.ahrq.gov/index.cfm/glossary-of-terms/> .

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[35.] Wilczynski NL, McKibbon KA, Haynes RB. Search filter precision can be improved by NOTing out irrelevant content. AMIA Annu Symp Proc. 2011 Nov:1506-13.

* This study was partially supported by grants awarded to Tanja Bekhuis from the National Institutes of Health, National Library of Medicine, grant no. 1K99LM010943-01A1 and grant no. 4R00LM010943-02.

([dagger]) A presentation describing this study was given to the American Medical Informatics Association (AMIA) 2012 Annual Symposium, November 3-7, Chicago, IL.

Supplemental Table 5 is available with the online version of this journal.

([double dagger]) The Agency for Healthcare Research and Quality (AHRQ) defines comparative effectiveness research as: "Comparative effectiveness research is designed to inform health-care decisions by providing evidence on the effectiveness, benefits, and harms of different treatment options. The evidence is generated from research studies that compare drugs, medical devices, tests, surgeries, or ways to deliver health care" [1].

Tanja Bekhuis, PhD, MS, MLIS; Dina Demner-Fushman, MD, PhD; Rebecca Crowley, MD, MS

Tanja Bekhuis, PhD, MS, MLIS, tcb24@pitt.edu, Assistant Professor, Department of Biomedical Informatics, School of Medicine, University of Pittsburgh, 5607 Baum Boulevard, Room 514, Pittsburgh, PA 15206; Dina Demner-Fushman, MD, PhD, dina.demner@nih.gov, Staff Scientist, Communications Engineering Branch (HNL32)Lister Hill National Center for Biomedical Communications, US National Library of Medicine, Building 38A, Room 10S1022, Mail Stop 3824, 8600 Rockville Pike, Bethesda, MD 20814; Rebecca S. Crowley, MD, MS, crowleyrs@upmc.edu, Associate Professor, Department of Biomedical Informatics, School of Medicine, University of Pittsburgh, 5607 Baum Boulevard, Room 523, Pittsburgh, PA 15206

Table 1

Comparative effectiveness research (CER) design terminology

                 Term                    Frequency of appearance
                                                in local
                                           terminologies (LTs)

adaptive design                                    (1)
analytic study                                     (3)
before-after study                                 (5)
case report                                        (3)
case series                                        (5)
case study                                         (1)
case-control study                                 (5)
cluster nonrandomized                              (1)
controlled trial
cluster quasi-randomized                           (1)
controlled trial
cluster randomized controlled trial                (3)
cluster randomized trial                           (2)
cohort before-and-after study                      (1)
cohort study                                       (3)
community trial                                    (2)
controlled before-after study                      (3)
controlled cohort                                  (1)
before-and-after study
controlled interrupted time series                 (1)
controlled trial                                   (1)
correlational study                                (1)
crossover study                                    (3)
cross-sectional study                              (5)
data base study                                    (1)
descriptive study                                  (4)
diagnostic study                                   (1)
double blinded randomized                          (1)
controlled trial
ecological cross-sectional study                   (1)
epidemiological study                              (1)
experimental study                                 (3)
factorial study                                    (2)
focus group                                        (1)
group randomized trial                             (3)
head-to-head study                                 (1)
historically controlled trial                      (1)
interrupted time series study                      (1)
interrupted time series with                       (2)
comparison group
interrupted time series without                    (2)
comparison group
meta-analysis                                      (2)
meta-analysis of individual                        (1)
participant data
modeling                                           (1)

                 Term                          Frequency of
                                            appearance in LTs

nested case-control study                          (3)
n-of-one trial                                     (2)
noncomparative study                               (4)
nonconcurrent cohort study                         (4)
non-controlled trial                               (2)
non-experimental study                             (1)
nonrandomized comparative trial                    (1)
nonrandomized controlled trial                     (3)
nonrandomized crossover trial                      (1)
nonrandomized trial                                (4)
observational study                                (4)
open-label randomized controlled trial             (1)
opinion paper                                      (1)
parallel study                                     (2)
pragmatic trial                                    (1)
pre-post study                                     (1)
prospective case series                            (1)
prospective cohort study                           (5)
quasi-experimental study                           (2)
quasi-randomized controlled trial                  (2)
quasi-randomized trial                             (2)
randomized clinical trial                          (1)
randomized controlled trial                        (5)
randomized crossover trial                         (1)
randomized trial                                   (4)
reliability study                                  (1)
retrospective case control study                   (1)
retrospective cohort study                         (5)
retrospective study                                (2)
simulation modeling                                (1)
single-blinded randomized                          (1)
controlled trial
solomon four-group study                           (2)
stepped wedge study                                (2)
systematic review                                  (2)
time series                                        (4)
time study                                         (1)
trend study                                        (2)
uncontrolled longitudinal study                    (1)
validity study                                     (1)

Table 2

Pairwise overlap of local terminologies: percentage overlap computed
as (n terms shared/n terms in either terminology) x 100

                    Agency for          Cochrane         Academy of
                    Healthcare       Non-Randomised    Nutrition and
                   Research and          Studies         Dietetics
                  Quality (ARHQ)      Methods Group        (ADA)
                                       (Cochrane)

Alberta          75.61%   (31/41)    57.89% (33/57)    32.69% (17/52)
AHRQ                                 24.56% (14/57)    31.58% (18/57)
Cochrane                                               30.77% (16/52)
ADA
RTI
Mean overall
pairwise
overlap

                    Research         Mean
                    Triangle       pairwise
                   Institute       overlap
                 International
                 University of
                 North Carolina
                 Evidence based
                Practice Center
                     (RTI)

Alberta         28.89%  (13/45)     48.77%
AHRQ            22.64%  (12/53)     38.60%
Cochrane        23.40%  (11/47)     34.16%
ADA             27.66%  (13/47)     30.68%
RTI                                 25.65%
Mean overall                        35.57%
pairwise
overlap

Table 3

Overlap of local terminologies with the CER design terminology:
percentage overlap computed as (n terms in the local terminology/n
terms in the union) x 100

   Alberta            AHRQ           Cochrane           ADA

42.31% (33/78)   50.00% (39/78)   41.03% (32/78)   46.15% (36/78)

    RTI          Mean overlap

32.05% (25/78)      42.31%

Table 4

Coverage of CER design terms by controlled vocabulary

 Type of match    Medical Subject        Emtree        MeSH to
                   Headings (MeSH)                   Emtree ratio

No match            14   (17.9%)      7     (9.0%)   2.00  (14/7)
Partial             49   (62.8%)      45   (57.7%)   1.09  (49/45)
Exact               15   (19.2%)      26   (33.3%)   0.58  (15/26)
Total               78  (100.0%)      78  (100.0%)

Table 5

Comparative effectiveness research (CER) designs in Medical Subject
Headings (MeSH) and Emtree: a crosswalk

Terms from
local CER
design            Example
terminologies *   variants ([dagger])       MeSH ID

adaptive design

analytic study    analytic                  D016021
                  studies

before-after      before-and-after          N
study             study; before-and-after
                  design;
                  before-and-after trial

case report                                 D002363

case series                                 D016896

case study                                  D002363

case-control      case control              D016022
study             study

cluster non-      cluster                   D018848
randomized        nonrandomized
controlled        controlled trial,
trial             cluster non-
                  randomised
                  controlled trial,
                  cluster
                  nonrandomised
                  controlled trial

cluster quasi-    example                   D018848
randomized        variants as
controlled        above
trial

cluster           cluster                   D016449
randomized        randomised
controlled        controlled trial
trial

cluster           cluster randomised        D016449
randomized        trial
trial

cohort before-    cohort before-            D015331
and-after study   after study

cohort study                                D015331

community trial

controlled        controlled                D018848
before-after      before-and-
study             after study

controlled        controlled                D015331
cohort before-    cohort before-
and-after study   after study

controlled                                  D008137
interrupted
time series

controlled                                  D018848
trial

correlational
study

crossover study   cross-over study,         D018592
                  crossover study design

cross-sectional                             D003430
study

data base study   database study            D019991

descriptive       descriptive studies
study

diagnostic                                  D016430
study

double blinded                              double blinded D004311
randomized                                  RCT
controlled
trial (RCT)

ecological                                  D003430
cross-sectional
study

epidemiological                             D016021
study

experimental      experimental studies,     D036262
study             experimental trial,
                  experimental trials

factorial study                             N

focus group       D017144                   E

group             group                     D016449
randomized        randomised
trial             trial

head-to-head      head-to-head studies
study

historically                                D015331
controlled
trial

interrupted                                 D008137
time series
study

interrupted                                 D008137
time series
with comparison
group

interrupted                                 D008137
time series
without
comparison
group

meta-analysis     metaanalysis, meta        D017418
                  analysis

meta-analysis     individual patient data   D017418
of individual     (IPD) meta-analysis,
participant       IPD review
data (MIPD)

modeling          modelling                 D008962

nested case-      nested case               D016022
control study     control study

n-of-one trial    n-of-1 trial

noncomparative    non-comparative study
study

nonconcurrent     non-concurrent cohort     D015331
cohort study      study

non-controlled    uncontrolled trial        D016430
trial

non-              non-
experimental      experimental
study             studies

nonrandomized     non-randomized            D003160
comparative       comparative trial, non-
trial             randomised comparative
                  trial, nonrandomised
                  comparative trial

nonrandomized     non-randomized            D018848
controlled        controlled trial, non-
trial             randomised controlled
                  trial, nonrandomised
                  controlled trial

non-randomized    nonrandomized crossover   D018592
crossover trial   trial, non-randomised
                  crossover trial,
                  nonrandomised crossover
                  trial

nonrandomized     non-randomized trial,     D016430
trial             nonrandomised trial,
                  non-randomised trial

observational     observational             D036301
study             studies

open-label RCT    open-label randomized     D016449
                  controlled trial

opinion paper                               D016421

parallel study

pragmatic trial

pre-post study    pre-and-post study        D005069

prospective                                 D016896
case series

prospective                                 D011446
cohort study

quasi-            quasi                     D036262
experimental      experimental
study             study

quasi-            quasi                     D018848
randomized        randomized
controlled        controlled trial
trial

quasi-            quasi                     D016430
randomized        randomized trial
trial

randomized        randomized                D016430
clinical trial    clinical trial
(RCT)

randomized        randomized controlled     D016449
controlled        trial RCT, randomised
trial             controlled trial

randomized        randomised crossover      D018592
crossover trial   trial

randomized        randomised trial          D016449
trial

reliability                                 D023361
study

retrospective     retrospective             D016022
case control      case-control
study             study

retrospective                               D012189
cohort study

retrospective                               D012189
study

simulation        simulation                D008962
modeling          model,
                  simulation
                  models

single-blinded    single-blinded            D016449
RCT               randomized
                  controlled trial

solomon four-     solomon four
group study       group study

stepped wedge
study

systematic                                  D016454
review

time series                                 D008137

time study                                  D013996

trend study                                 D018571

uncontrolled                                D008137
longitudinal
study

validity study                              D023361

Terms from
local CER
design            MeSH                      Comment on
terminologies *   match ([double dagger])   MeSH match

adaptive design   N

analytic study    P                         Consider other MeSH
                                            terms, see scope note
                                            here.

before-after      See CER design term
study             "pre-post study" for
                  possible alternatives
                  (first column, this
                  table).

case report       E

case series       P

case study        E

case-control      E
study

cluster non-      P                         Detail, negation,
randomized                                  mapped term
controlled                                  may be
trial                                       inappropriate
                                            when trial focus
                                            is on groups
                                            rather than
                                            individuals.

cluster quasi-    P                         Detail, mapped
randomized                                  term may be
controlled                                  inappropriate
trial                                       when trial focus
                                            is on groups
                                            rather than
                                            individuals.

cluster           P                         Detail, try adding
randomized                                  "cluster" as
controlled                                  keyword to MeSH
trial                                       term.

cluster           P
randomized
trial

cohort before-    P                         detail
and-after study

cohort study      E

community trial   N

controlled        P                         Detail, mapped term may
before-after                                be inappropriate. Try
study                                       "Longitudinal Studies"
                                            (D008137)

controlled        P                         Detail, try
cohort before-                              "Longitudinal
and-after study                             Studies" (D008137)

controlled        P                         Detail
interrupted
time series

controlled        P                         Mapped term
trial                                       may be
                                            inappropriate when a
                                            study does not concern
                                            individuals.

correlational     N                         Entry terms
study                                       "correlation study" and
                                            "correlation studies"
                                            under "Statistics as
                                            Topic" not relevant.

crossover study   E

cross-sectional   E
study

data base study   P                         Try "Clinical Audit"'
                                            (D054869) or
                                            "Registries" (D012042).

descriptive       N
study

diagnostic        P                         Try "Validation
study                                       Studies" D023361

double blinded    P                         Detail, try adding
randomized                                  "Randomized Controlled
controlled                                  Trial" D016449
trial (RCT)

ecological        P                         Detail
cross-sectional
study

epidemiological   E
study

experimental      P
study

factorial study

focus group       Focus Groups

group             P                         Mapped term
randomized                                  may be
trial                                       inappropriate
                                            when focus of
                                            trial is on groups
                                            rather than
                                            individuals.

head-to-head      N                         Try "Comparative Study"
study                                       D003160

historically      P                         Try "Retrospective
controlled                                  Studies" D012189
trial

interrupted       P                         Detail, see also CER
time series                                 design term "time
study                                       series" (first column,
                                            this table).

interrupted       P                         Detail, try
time series                                 "Comparative Study"
with comparison                             D003160; see also CER
group                                       design term "time
                                            series" (first column,
                                            this table).

interrupted       P                         Detail, negation; see
time series                                 also CER design term
without                                     "time series" (first
comparison                                  column, this table).
group

meta-analysis     E

meta-analysis     P                         detail
of individual
participant
data (MIPD)

modeling          P                         Try searching for
                                            "model" at
                                            www.nlm.nih.gov/mesh/
                                            MBrowser.html for list
                                            of models.

nested case-      E                         Detail.
control study

n-of-one trial    N                         Try "Case Reports"
                                            D002363

noncomparative    N                         Negation, try
study                                       "Qualitative Research"
                                            D036301

nonconcurrent     P                         Negation
cohort study

non-controlled    P                         Negation
trial

non-              N                         Negation; try
experimental                                "Qualitative
study                                       Research" D036301

nonrandomized     P                         Negation
comparative
trial

nonrandomized     P                         Negation, mapped term
controlled                                  may be inappropriate
trial                                       when a study is not
                                            clinical.

non-randomized    P                         Negation
crossover trial

nonrandomized     P                         Negation
trial

observational     P
study

open-label RCT    P                         Detail

opinion paper     P                         Try "Comment"
                                            (D016420), "Consensus"
                                            (D032921), or "Letter"
                                            (D016422)

parallel study    N

pragmatic trial   N                         Try "Comparative Study"
                                            D003160

pre-post study    P                         "Evaluation Studies"
                                            (D023362) may be more
                                            relevant than
                                            "Evaluation Studies as
                                            Topic," also consider
                                            "Longitudinal Studies"
                                            (D008137).

prospective       P
case series

prospective       P                         Try "Cohort
cohort study                                Studies" (D015331)

quasi-            P
experimental
study

quasi-            P
randomized
controlled
trial

quasi-            P
randomized
trial

randomized        P                         Here, RCT stands for
clinical trial                              randomized clinical
(RCT)                                       trial, rather than
                                            randomized controlled
                                            trial, consider using
                                            "Randomized Controlled
                                            Trial" instead.

randomized        E
controlled
trial

randomized        P
crossover trial

randomized        P
trial

reliability       P                         Try "Psychometrics" for
study                                       psychological, social,
                                            or behavioral
                                            measurement studies
                                            (D011594); try
                                            "Reproducibility of
                                            Results" (D015203).

retrospective     P                         Detail, try
case control                                "Retrospective
study                                       Studies" D012189

retrospective     P                         Try "Cohort
cohort study                                Studies" (D015331)

retrospective     E
study

simulation        P                         Try searching for
modeling                                    "model" at
                                            www.nlm.nih.gov/
                                            mesh/MBrowser
                                            .html for list of
                                            models.

single-blinded    P                         Detail, try
RCT                                         combining with
                                            "Single-Blind
                                            Method"
                                            D016037

solomon four-     N                         Detail
group study

stepped wedge     N
study

systematic        E
review

time series       P                         Try "Models,
                                            Statistical"
                                            D015233

time study        E                         "Longitudinal Studies"
                                            or "Models,
                                            Statistical" may be
                                            more relevant.

trend study       P                         "Longitudinal Studies"
                                            or "Models,
                                            Statistical" may be
                                            more relevant.

uncontrolled      P                         Negation
longitudinal
study

validity study    E                         Try "Psychometrics" for
                                            psychological, social,
                                            or behavioral
                                            measurement studies
                                            (D011594), try
                                            "Reproducibility of
                                            Results" (D015203).

Terms from
local CER
design            MeSH
terminologies *   heading                   MeSH entry term

adaptive design

analytic study    Epidemiologic Studies     Epidemiological
                                            Studies; Studies,
                                            Epidemiologic

before-after
study

case report       Case Reports              Case Histories, Case
                                            Studies, Case Study

case series       Treatment Outcome         Rehabilitation Outcome,
                                            Treatment
                                            Effectiveness,
                                            Treatment Efficacy

case study        Case Reports              Case Histories, Case
                                            Studies, Case Study

case-control      Case-Control              Case Control Studies,
study             Studies                   Case-Base Studies,
                                            Case-Comparison
                                            Studies, Case-Compeer
                                            Studies, Case-Referent
                                            Studies, Case-Referrent
                                            Studies, Matched
                                            Case-Control Studies,
                                            Nested Case-Control
                                            Studies

cluster non-      Controlled
randomized        Clinical Trial
controlled
trial

cluster quasi-    Controlled
randomized        Clinical Trial
controlled
trial

cluster           Randomized
randomized        Controlled
controlled        Trial
trial

cluster           Randomized Controlled
randomized        Trial
trial

cohort before-    Cohort                    Analysis, Cohort;
and-after study   Studies                   Closed Cohort Studies;
                                            Cohort Analysis; Cohort
                                            Studies, Closed; Cohort
                                            Studies, Historical;
                                            Concurrent Studies;
                                            Historical Cohort
                                            Studies; Incidence
                                            Studies; Studies,
                                            Closed Cohort; Studies,
                                            Concurrent; Studies,
                                            Historical Cohort

cohort study      Cohort Studies            Analysis, Cohort;
                                            Closed Cohort Studies;
                                            Cohort Analysis; Cohort
                                            Studies, Closed; Cohort
                                            Studies, Historical;
                                            Concurrent Studies;
                                            Historical Cohort
                                            Studies; Incidence
                                            Studies; Studies,
                                            Closed Cohort; Studies,
                                            Concurrent; Studies,
                                            Historical Cohort

community trial

controlled        Controlled
before-after      Clinical Trial
study

controlled        Cohort                    Analysis, Cohort;
cohort before-    Studies                   Closed Cohort Studies;
and-after study                             Cohort Analysis; Cohort
                                            Studies, Closed; Cohort
                                            Studies, Historical;
                                            Concurrent Studies;
                                            Historical Cohort
                                            Studies; Incidence
                                            Studies; Studies,
                                            Closed Cohort; Studies,
                                            Concurrent; Studies,
                                            Historical Cohort

controlled        Longitudinal              Longitudinal Survey
interrupted       Studies
time series

controlled        Controlled
trial             Clinical Trial

correlational
study

crossover study   Cross-Over Studies        Cross-Over Design,
                                            Cross-Over Trials,
                                            Crossover Design,
                                            Crossover Studies,
                                            Crossover Trials

cross-sectional   Cross-Sectional Studies   Analysis, Cross-
study                                       Sectional; Cross
                                            Sectional Analysis;
                                            Cross-Sectional Survey;
                                            Disease Frequency
                                            Surveys; Prevalence
                                            Studies; Surveys,
                                            Disease Frequency

data base study   Database                  Data Base

descriptive
study

diagnostic        Clinical Trial
study

double blinded    Double-Blind              Double-Blind Study,
randomized        Method                    Double-Masked
controlled                                  Method, Double-
trial (RCT)                                 Masked Study

ecological        Cross-Sectional Studies   Analysis, Cross-
cross-sectional                             Sectional; Cross
study                                       Sectional Analysis;
                                            Cross-Sectional Survey;
                                            Disease Frequency
                                            Surveys; Prevalence
                                            Studies; Surveys,
                                            Disease Frequency

epidemiological   Epidemiologic             Epidemiological
study             Studies                   Studies; Studies,
                                            Epidemiologic

experimental      Empirical
study             Research

factorial study

focus group

group             Randomized
randomized        Controlled
trial             Trial

head-to-head
study

historically      Cohort                    Analysis, Cohort;
controlled        Studies                   Closed Cohort Studies;
trial                                       Cohort Analysis; Cohort
                                            Studies, Closed; Cohort
                                            Studies, Historical;
                                            Concurrent Studies;
                                            Historical Cohort
                                            Studies; Incidence
                                            Studies; Studies,
                                            Closed Cohort; Studies,
                                            Concurrent; Studies,
                                            Historical Cohort

interrupted       Longitudinal              Longitudinal Survey
time series       Studies
study

interrupted       Longitudinal              Longitudinal Survey
time series       Studies
with comparison
group

interrupted       Longitudinal              Longitudinal Survey
time series       Studies
without
comparison
group

meta-analysis     Meta-Analysis

meta-analysis     Meta-Analysis
of individual
participant
data (MIPD)

modeling          Models, Theoretical       Experimental Model;
                                            Experimental Models;
                                            Mathematical Model;
                                            Model, Experimental;
                                            Models (Theoretical);
                                            Models, Experimental;
                                            Models, Theoretic;
                                            Theoretical Study

nested case-      Case-Control Studies      Case Control Studies,
control study                               Case-Base Studies,
                                            Case-Comparison
                                            Studies, Case-Compeer
                                            Studies, Case-Referent
                                            Studies, Case-
                                            Referrent Studies,
                                            Matched Case-Control
                                            Studies, Nested Case-
                                            Control Studies

n-of-one trial

noncomparative
study

nonconcurrent     Cohort                    Analysis, Cohort;
cohort study      Studies                   Closed Cohort Studies;
                                            Cohort Analysis; Cohort
                                            Studies, Closed; Cohort
                                            Studies, Historical;
                                            Concurrent Studies;
                                            Historical Cohort
                                            Studies; Incidence
                                            Studies; Studies,
                                            Closed Cohort; Studies,
                                            Concurrent; Studies,
                                            Historical Cohort

non-controlled    Clinical Trial
trial

non-
experimental
study

nonrandomized     Comparative               Comparative
comparative       Study                     Studies
trial

nonrandomized     Controlled
controlled        Clinical Trial
trial

non-randomized    Cross-Over                Cross-Over Design,
crossover trial   Studies                   Cross-Over Trials,
                                            Crossover Design,
                                            Crossover Studies,
                                            Crossover Trials

nonrandomized     Clinical Trial
trial

observational     Qualitative               Research that derives
study             Research                  data from observation,
                                            interviews, or verbal
                                            interactions and
                                            focuses on the meanings
                                            and interpretations of
                                            the participants.

open-label RCT    Randomized Controlled
                  Trial

opinion paper     Editorial

parallel study

pragmatic trial

pre-post study    Evaluation Studies as     Critique, Evaluation,
                  Topic                     Evaluation Indexes,
                                            Evaluation Methodology,
                                            Evaluation Report,
                                            Evaluation Research,
                                            Methodology,
                                            Evaluation, Pre-Post
                                            Tests Qualitative
                                            Evaluation,
                                            Quantitative
                                            Evaluation, Theoretical
                                            Effectiveness, Use-
                                            Effectiveness

prospective       Treatment                 Rehabilitation Outcome,
case series       Outcome                   Treatment
                                            Effectiveness,
                                            Treatment Efficacy

prospective       Prospective
cohort study      Studies

quasi-            Empirical
experimental      Research
study

quasi-            Controlled
randomized        Clinical Trial
controlled
trial

quasi-            Clinical Trial
randomized
trial

randomized        Clinical Trial
clinical trial
(RCT)

randomized        Randomized
controlled        Controlled Trial
trial

randomized        Cross-Over Studies        Cross-Over Design,
crossover trial                             Cross-Over Trials,
                                            Crossover Design,
                                            Crossover Studies,
                                            Crossover Trials

randomized        Randomized Controlled
trial             Trial

reliability       Validation Studies
study

retrospective     Case-Control              Case Control Studies,
case control      Studies                   Case-Base Studies,
study                                       Case-Comparison
                                            Studies, Case-Compeer
                                            Studies, Case-Referent
                                            Studies, Case-
                                            Referrent Studies,
                                            Matched Case-Control
                                            Studies, Nested Case-
                                            Control Studies

retrospective     Retrospective             Retrospective Study
cohort study      Studies

retrospective     Retrospective             Retrospective Study
study             Studies

simulation        Models,                   Experimental
modeling          Theoretical               Model;
                                            Experimental
                                            Models;
                                            Mathematical
                                            Model; Model,
                                            Experimental;
                                            Models
                                            (Theoretical);
                                            Models,
                                            Experimental;
                                            Models, Theoretic;
                                            Theoretical Study

single-blinded    Randomized
RCT               Controlled
                  Trial

solomon four-
group study

stepped wedge
study

systematic        Review                    Review, Systematic
review

time series       Longitudinal              Longitudinal Survey
                  Studies

time study        Time and Motion Studies   Time Studies

trend study       Sentinel Surveillance     Sentinel Health Event

uncontrolled      Longitudinal              Longitudinal Survey
longitudinal      Studies
study

validity study    Validation Studies

Terms from
local CER
design                                      Emtree
terminologies *   MeSH scope note           match ([section])

adaptive design                             N

analytic study    Studies designed to       P
                  examine associations,
                  commonly hypothesized
                  causal relations. They
                  are usually concerned
                  with identifying or
                  measuring the effects
                  of risk factors or
                  exposures. The common
                  types of analytic study
                  are CASE-CONTROL
                  STUDIES; COHORT
                  STUDIES; and
                  CROSS-SECTIONAL
                  STUDIES.

before-after      N                         See CER design term
study                                       "pre-post study" for
                                            possible alternatives
                                            (first column, this
                                            table).

case report                                 E

case series       Evaluation undertaken     E
                  to assess the results
                  or consequences of
                  management and
                  procedures used in
                  combating disease in
                  order to determine the
                  efficacy,
                  effectiveness, safety,
                  practicability, etc.,
                  of these interventions
                  in individual cases or
                  series.

case study                                  E

case-control                                E
study

cluster non-                                P
randomized
controlled
trial

cluster quasi-                              P
randomized
controlled
trial

cluster                                     P
randomized
controlled
trial

cluster                                     P
randomized
trial

cohort before-    Detail, see CER design    P
and-after study   term "before-after
                  study" (first column,
                  this table) for
                  possible alternatives.

cohort study                                E

community trial                             E

controlled                                  P
before-after
study

controlled                                  P
cohort before-
and-after study

controlled        Studies in which          P
interrupted       variables relating to
time series       an individual or group
                  of individuals are
                  assessed over a period
                  of time.

controlled                                  E
trial

correlational                               E
study

crossover study                             E

cross-sectional                             E
study

data base study                             P

descriptive                                 P
study

diagnostic        Work that is the report   P
study             of a preplanned
                  clinical study of the
                  safety, efficacy, or
                  optimum dosage schedule
                  of one or more
                  diagnostic,
                  therapeutic, or
                  prophylactic drugs,
                  devices, or techniques
                  in humans selected
                  according to
                  predetermined criteria
                  of eligibility and
                  observed for predefined
                  evidence of favorable
                  and unfavorable
                  effects. While most
                  clinical trials concern
                  humans, this
                  publication type may be
                  used for clinical
                  veterinary articles
                  meeting the requisites
                  for humans. Specific
                  headings for specific
                  types and phases of
                  clinical trials are
                  also available.

double blinded                              P
randomized
controlled
trial (RCT)

ecological                                  P
cross-sectional
study

epidemiological                             P
study

experimental      The study, based on       E
study             direct observation, use
                  of statistical records,
                  interviews, or
                  experimental methods,
                  of actual practices or
                  the actual impact of
                  practices or policies.

factorial study                             E

focus group                                 E

group                                       P
randomized
trial

head-to-head                                N
study

historically                                P
controlled
trial

interrupted       Studies in which          P
time series       variables relating to
study             an individual or group
                  of individuals are
                  assessed over a period
                  of time.

interrupted       Studies in which          P
time series       variables relating to
with comparison   an individual or group
group             of individuals are
                  assessed over a period
                  of time.

interrupted       Studies in which          P
time series       variables relating to
without           an individual or group
comparison        of individuals are
group             assessed over a period
                  of time.

meta-analysis                               E

meta-analysis                               P
of individual
participant
data (MIPD)

modeling                                    E

nested case-                                P
control study

n-of-one trial                              N

noncomparative                              P
study

nonconcurrent                               P
cohort study

non-controlled                              P
trial

non-                                        E
experimental
study

nonrandomized                               P
comparative
trial

nonrandomized                               P
controlled
trial

non-randomized                              P
crossover trial

nonrandomized                               P
trial

observational                               E
study

open-label RCT                              P

opinion paper     Work consisting of a      N
                  statement of the
                  opinions, beliefs, and
                  policy of the editor or
                  publisher of a journal,
                  usually on current
                  matters of medical or
                  scientific significance
                  to the medical
                  community or society at
                  large. The editorials
                  published by editors of
                  journals representing
                  the official organ of a
                  society or organization
                  are generally
                  substantive.

parallel study                              E

pragmatic trial                             N

pre-post study                              P

prospective       Evaluation undertaken     P
case series       to assess the results
                  or consequences of
                  management and
                  procedures used in
                  combating disease in
                  order to determine the
                  efficacy,
                  effectiveness, safety,
                  practicability, etc.,
                  of these interventions
                  in individual cases or
                  series.

prospective                                 P
cohort study

quasi-            The study, based on       E
experimental      direct observation, use
study             of statistical records,
                  interviews, or
                  experimental methods of
                  actual practices or the
                  actual impact of
                  practices or policies.

quasi-                                      P
randomized
controlled
trial

quasi-                                      P
randomized
trial

randomized                                  P
clinical trial
(RCT)

randomized                                  E
controlled
trial

randomized                                  P
crossover trial

randomized        Work consisting of a      P
trial             clinical trial that
                  involves at least one
                  test treatment and one
                  control treatment,
                  concurrent enrollment
                  and follow-up of the
                  test-and control-
                  treated groups, and in
                  which the treatments to
                  be administered are
                  selected by a random
                  process,such as the use
                  of a random-numbers
                  table.

reliability       Works consisting of       P
study             research using
                  processes by which the
                  reliability and
                  relevance of a
                  procedure for a
                  specific purpose are
                  established.

retrospective                               P
case control
study

retrospective                               P
cohort study

retrospective                               E
study

simulation                                  E
modeling

single-blinded                              P
RCT

solomon four-                               P
group study

stepped wedge                               N
study

systematic                                  E
review

time series       Studies in which          E
                  variables relating to
                  an individual or group
                  of individuals are
                  assessed over a period
                  of time.

time study                                  P

trend study       Monitoring of rate of     E
                  occurrence of specific
                  conditions to assess
                  the stability or change
                  in health levels of a
                  population. It is also
                  the study of disease
                  rates in a specific
                  cohort, geographic
                  area, population
                  subgroup, etc., to
                  estimate trends in
                  larger population.

uncontrolled                                P
longitudinal
study

validity study                              E

Terms from
local CER
design            Comment on
terminologies *   Emtree match              Emtree term

adaptive design

analytic study    Mapped term not a         analytical
                  design per se, but
                  refers to a broad
                  research domain.

before-after
study

case report                                 case report

case series                                 case study

case study                                  case study

case-control                                case control
study                                       study

cluster non-      detail, negation          controlled
randomized                                  study,
controlled                                  controlled
trial                                       clinical trial

cluster quasi-    detail                    quasi
randomized                                  experimental
controlled                                  study
trial

cluster           detail                    randomized
randomized                                  controlled
controlled                                  trial
trial

cluster                                     randomized controlled
randomized                                  trial
trial

cohort before-    Detail, see CER design    cohort
and-after study   term "before-after        analysis
                  study" (first column,
                  this table) for
                  possible alternatives.

cohort study                                cohort analysis

community trial                             community trial

controlled        Detail, try               controlled
before-after      "pretest posttest         study
study             control group design."

controlled        Detail, try               cohort
cohort before-    "pretest posttest         analysis,
and-after study   control group design."    controlled study

controlled        Detail, try               time series
interrupted       "longitudinal             analysis
time series       study."

controlled                                  controlled study
trial

correlational                               correlational
study                                       study

crossover study                             crossover procedure

cross-sectional                             cross-sectional study
study

data base study   Try: "medical audit,"     data base
                  "medical record
                  review," "hospital
                  based case control
                  study," "disease
                  registry."

descriptive       Mapped term not a         descriptive research
study             design per se, but
                  refers to a broad
                  research domain.

diagnostic                                  diagnostic test
study                                       accuracy study

double blinded    Detail, try adding        double blind
randomized        "randomized               procedure
controlled        controlled trial."
trial (RCT)

ecological        detail                    cross-
cross-sectional                             sectional study
study

epidemiological   Mapped term               cross-
study             may not be relevant.      sectional study

experimental                                experimental
study                                       study

factorial study                             factorial design

focus group       Try "interview."          information processing

group             Try "community            randomized
randomized        trial" if                 controlled trial
trial             intervention
                  randomly
                  assigned to
                  intact groups.

head-to-head      Try "comparative study"
study

historically                                controlled
controlled                                  study
trial

interrupted       Detail, try               time series
time series       "longitudinal study."     analysis
study

interrupted       Detail, try               time series
time series       "longitudinal             analysis
with comparison   study."
group

interrupted       Detail, negation;         time series
time series       try "longitudinal         analysis
without           study"
comparison
group

meta-analysis                               meta analysis

meta-analysis     detail                    meta analysis
of individual
participant
data (MIPD)

modeling                                    model

nested case-      detail                    case control
control study                               study

n-of-one trial    Try "case report"

noncomparative    negation                  observational
study                                       study

nonconcurrent     negation                  cohort
cohort study                                analysis

non-controlled    negation                  clinical trial
trial

non-              negation,                 observational
experimental      although maps             study
study             to a relevant term

nonrandomized     negation                  comparative
comparative                                 study
trial

nonrandomized     negation                  controlled study,
controlled                                  controlled clinical
trial                                       trial

non-randomized    negation                  crossover
crossover trial                             procedure

nonrandomized     negation                  clinical trial
trial

observational                               observational
study                                       study

open-label RCT    Detail, try combining     open study
                  with "randomized
                  controlled trial."

opinion paper     Try "editorial,"
                  "consensus," "consensus
                  development."

parallel study                              parallel design

pragmatic trial   Try "comparative
                  study."

pre-post study                              pretest posttest design

prospective                                 case study
case series

prospective                                 prospective
cohort study                                study

quasi-                                      quasi
experimental                                experimental
study                                       study

quasi-                                      controlled
randomized                                  study
controlled
trial

quasi-                                      quasi
randomized                                  experimental study
trial

randomized        Here, RCT stands for      clinical trial
clinical trial    randomized clinical
(RCT)             trial, rather than
                  randomized controlled
                  trial, consider using
                  "randomized controlled
                  trial."

randomized                                  randomized
controlled                                  controlled trial
trial

randomized                                  crossover procedure
crossover trial

randomized                                  randomized controlled
trial                                       trial

reliability       Mapped term refers to a   reliability
study             statistical concept
                  rather than a design,
                  may not be relevant,
                  try "psychometry" where
                  appropriate.

retrospective     Detail, try               case control
case control      "retrospective            study
study             study."

retrospective     Try "cohort               retrospective
cohort study      analysis."                study

retrospective                               retrospective
study                                       study

simulation                                  simulation
modeling

single-blinded    Detail, try               randomized
RCT               combining with            controlled trial
                  "single blind
                  procedure."

solomon four-     Detail, although          pretest
group study       maps to a more            posttest
                  detailed term.            control group
                                            design

stepped wedge
study

systematic                                  systematic review
review

time series       Try "longitudinal         time series
                  study" or                 analysis
                  "statistical model."

time study        "Longitudinal study,"     task performance
                  "time series analysis,"
                  or "statistical model"
                  may be more relevant.

trend study                                 trend study

uncontrolled      negation                  longitudinal
longitudinal                                study
study

validity study    Try "psychometry" where   validation study
                  appropriate.

Terms from
local CER
design            Emtree
terminologies *   synonym

adaptive design

analytic study    analytic research

before-after
study

case report

case series       case series, case
                  studies, large case
                  series

case study        case series, case
                  studies, large case
                  series

case-control      case-control studies;
study             case-control study;
                  control study, case;
                  matched case control;
                  matched case control
                  studies; matched case
                  control study

cluster non-      controlled trial;
randomized        clinical trial,
controlled        controlled
trial

cluster quasi-    Quasiexperi-
randomized        mental study
controlled
trial

cluster           controlled trial,
randomized        randomized;
controlled        randomised
trial             controlled trial;
                  trial, randomized
                  controlled

cluster           controlled trial,
randomized        randomized; randomised
trial             controlled trial;
                  trial, randomized
                  controlled

cohort before-    analysis, cohort;
and-after study   cohort fertility;
                  cohort life cycle;
                  cohort studies; cohort
                  study; fertility,
                  cohort

cohort study      analysis, cohort;
                  cohort fertility;
                  cohort life cycle;
                  cohort studies; cohort
                  study; fertility,
                  cohort

community trial

controlled        controlled trial
before-after
study

controlled        analysis, cohort;
cohort before-    cohort fertility;
and-after study   cohort life cycle;
                  cohort studies; cohort
                  study; fertility,
                  cohort; controlled
                  trial

controlled        multiple time
interrupted       series, time
time series       series

controlled        controlled trial
trial

correlational     correlation studies,
study             correlation study,
                  correlational studies

crossover study   cross-over studies;
                  cross over study;
                  crossover design;
                  crossover study;
                  crossover trial; double
                  blind crossover study;
                  procedure, crossover

cross-sectional   cross-sectional design,
study             cross-sectional
                  research, cross-
                  sectional studies

data base study   data bank, data
                  warehouse, database,
                  database construction,
                  database management
                  software, database
                  management systems,
                  database system;
                  databases, databases as
                  topic

descriptive
study

diagnostic
study

double blinded    double-blind
randomized        method, double
controlled        blind clinical trial,
trial (RCT)       double blind
                  comparison, double
                  blind studies, double
                  blind study, double
                  blind test, double
                  blind trial

ecological        cross-sectional design,
cross-sectional   cross-sectional
study             research, cross-
                  sectional studies

epidemiological   cross-sectional design,
study             cross-sectional
                  research, cross-
                  sectional studies

experimental      experimental
study             studies

factorial study

focus group       automatic data
                  processing;
                  computer data
                  processing;
                  computer
                  processing; data
                  acquisition; data
                  collection; data
                  collection site;
                  data
                  compression;
                  data conversion;
                  data display; data
                  fitting; data
                  handling; data
                  logging; data
                  management;
                  data processing;
                  data processing
                  system; data
                  recording; data
                  reporting; data
                  sampling; data
                  scanning; data
                  storage; data
                  system; date
                  identification;
                  electronic data
                  processing;
                  electronical data
                  processing;

                  focus groups;
                  idc index system;
                  information
                  processing
                  system;
                  laboratory data
                  processing;
                  punched-card
                  systems;
                  recording, data;
                  records; records
                  as topic

group             controlled trial,
randomized        randomized;
trial             randomised
                  controlled trial;
                  trial, randomized
                  controlled

head-to-head
study

historically      controlled trial
controlled
trial

interrupted       multiple time
time series       series, time series
study

interrupted       multiple time
time series       series, time
with comparison   series
group

interrupted       multiple time
time series       series; time
without           series
comparison
group

meta-analysis     analysis, meta; meta-
                  analysis; metaanalysis

meta-analysis     analysis, meta;
of individual     meta-analysis;
participant       metaanalysis
data (MIPD)

modeling          modeling; modelling;
                  models, nursing

nested case-      case-control studies;
control study     case-control study;
                  control study, case;
                  matched case control;
                  matched case control
                  studies; matched case
                  control study

n-of-one trial

noncomparative    non experimental
study             studies, non
                  experimental study,
                  nonexperimental
                  studies,
                  nonexperimental study,
                  observation studies,
                  observation study,
                  observational studies

nonconcurrent     analysis, cohort;
cohort study      cohort fertility;
                  cohort life cycle;
                  cohort studies; cohort
                  study; fertility,
                  cohort

non-controlled    trial, clinical
trial

non-              non experimental
experimental      studies, non
study             experimental study,
                  nonexperimental
                  studies,
                  nonexperimental study,
                  observation studies,
                  observation study,
                  observational studies

nonrandomized     comparative
comparative       studies, comparison
trial

nonrandomized     controlled trial;
controlled        clinical trial,
trial             controlled

non-randomized    cross-over studies;
crossover trial   cross over study;
                  crossover design;
                  crossover study;
                  crossover trial; double
                  blind crossover study;
                  procedure, crossover

nonrandomized     trial, clinical
trial

observational     non experimental
study             studies, non
                  experimental study,
                  nonexperimental
                  studies,
                  nonexperimental study,
                  observation studies,
                  observation study,
                  observational studies

open-label RCT    open-label clinical
                  trial, open-label
                  study, open-label
                  trial, open clinical
                  trial, open trial

opinion paper

parallel study

pragmatic trial

pre-post study    pretest posttest study

prospective       case series, case
case series       studies, large case
                  series

prospective
cohort study

quasi-            Quasiexperimental
experimental      study
study

quasi-            controlled trial
randomized
controlled
trial

quasi-            Quasiexperimental
randomized        study
trial

randomized        trial, clinical
clinical trial
(RCT)

randomized        controlled trial,
controlled        randomized; randomised
trial             controlled trial;
                  trial, randomized
                  controlled

randomized        cross-over studies;
crossover trial   cross over study;
                  crossover design;
                  crossover study;
                  crossover trial; double
                  blind crossover study;
                  procedure, crossover

randomized        controlled trial,
trial             randomized; randomised
                  controlled trial;
                  trial, randomized
                  controlled

reliability
study

retrospective     case-control studies;
case control      case-control study;
study             control study, case;
                  matched case control;
                  matched case control
                  studies; matched case
                  control study

retrospective     ex post facto design;
cohort study      retrospective design;
                  retrospective panel
                  studies; retrospective
                  panel study;
                  retrospective studies;
                  study, retrospective

retrospective     ex post facto design;
study             retrospective design;
                  retrospective panel
                  studies; retrospective
                  panel study;
                  retrospective studies;
                  study, retrospective

simulation        Simulate,
modeling          simulation model

single-blinded    controlled trial,
RCT               randomized;
                  randomised
                  controlled trial;
                  trial, randomized
                  controlled
solomon four-     pretest posttest
group study       control group
                  study

stepped wedge
study

systematic        review, systematic
review

time series       multiple time
                  series, time
                  series

time study        performance, task; task
                  performance and
                  analysis; test
                  performance; time and
                  motion studies; work
                  sampling; work
                  simplification

trend study       trend studies

uncontrolled      longitudinal
longitudinal      evaluation,
study             longitudinal studies

validity study    validation studies,
                  validation studies as
                  topic

* From 5 CER organizations. See paper for details.

([dagger]) Consider US and British spellings; hyphenation; no
hyphenation, including closed (no space) and open (space, but no
hyphen); singular and plural; acronyms. For keyword searches, try
study, studies, design, designs, trial, trials. Listed examples are
not exhaustive.

([double dagger]) E = exact; P = partial; N = no match. Exact match
if CER term directly maps to a MeSH heading or entry term (may map
to a spelling variant). Partial match if maps to a broader or related
term, or to a substring in a scope note.

([section]) Exact match if CER term directly maps to an Emtree term
or synonym (may map to a spelling variant). Partial match if maps to
a broader or related term.

Figure 1

Comparative effectiveness research (CER) design terms by appearance
in local terminologies

Number of       Number of
CER design        local
   terms      terminologies
                in which
               CER design
              terms appear

     1             37
     2             17
     3              9
     4              8
     5              7

Note: Table made from bar graph.
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Article Details
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Author:Bekhuis, Tanja; Demner-Fushman, Dina; Crowley, Rebecca
Publication:Journal of the Medical Library Association
Article Type:Report
Geographic Code:1USA
Date:Apr 1, 2013
Words:11070
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