The impact of free access to the scientific literature: a review of recent research.
A principal argument in support of open access publishing rests on the belief that the subscription-based publishing model has produced a crisis of accessibility to the scientific literature [1-6]. This paper evaluates that claim, reviewing the current literature and showing the ways in which free access has (or has not) had an impact on scholars, clinicians, and the general public in developed and developing nations.
The review assesses impact in terms of reading, citation, and related forms of use. It does not evaluate the extent to which the freely available scientific literature is technically accessible, indexed, cataloged, or available for potential use. The discussion deals only with the scholarly literature, thereby excluding studies of online newspapers, magazines, and trade publications. It also focuses on the natural sciences, since most of the research on free access has dealt with fields such as the biomedical, physical, and computer sciences. Although "open access" is the usual term for scholarly work that is freely accessible online, the term "free access" is used here, since open access is often understood to include issues of copyright, archiving, funding, and social justice that are not addressed in this discussion.
The paper first reviews the impact of free access on the research practices of scholars in developed and developing nations, then examines the use of freely available biomedical literature by health professionals and the lay public. It concludes with a discussion of avenues for further research.
The analysis is based on a review of current empirical studies (January 2001 through December 2010) that attempt to measure--directly or indirectly--access to and use of the scientific literature by academics, clinicians, and the lay public. Relevant works were identified from several sources: bibliographic data-bases, cited references, personal correspondence, and prior experience with the topic. Studies of how information is produced, published, and made publicly available, such as papers on the economics of scientific publishing, are excluded. Also excluded are works that rely solely on personal convictions and anecdotal evidence, as well as those that report redundant findings (such as conference presentations, posters, and summary reports).
APPROACHES TO STUDYING SCHOLARS' USE OF THE SCIENTIFIC LITERATURE
Current research on the use of the scientific literature follows two main methodological approaches. The first makes use of surveys and interviews to examine scholars' perceptions and opinions of the scholarly communication system. The second relies on bibliometric evidence--on unobtrusive studies of what scientists download, read, and cite.
Each approach has both strengths and weaknesses. Surveys can be used to elicit the responses of thousands of individuals in order to draw conclusions about a target population. In-depth interviews, while limited in their generalizability, can be used to explore a topic in detail and to examine the values and motivations of interview participants. Nonetheless, poorly constructed or poorly executed surveys and interviews are susceptible to many forms of bias, including sampling bias (the inability to reach a representative target audience); nonresponse bias (the underrepresentation of particular subgroups in the sample); response bias (bias associated with the survey instrument itself--the framing, formulation, and ordering of survey questions, for example); acquiescence bias (the tendency for respondents, when in doubt, to respond in the affirmative); and social desirability bias (the tendency for respondents to provide a response they believe to be socially supportive), among others [7, 8]. Many of the studies described in this review suffer from one or more forms of bias.
Unobtrusive methods, such as counting article downloads or citations, offer a more direct approach to measuring what scientists actually do, rather than what they say they do. While these methods avoid the potential biases of survey and interview research, many forms of unobtrusive methods are susceptible to limitations of their own, the most common of which is interpretive. Downloads are often equated with reading, for example, yet this connection is purely inferential. Devoid of context, a download statistic does not reveal who was responsible for the download (or whether the agent was even human), why the article was downloaded, or how the article was used (if it was used at all). Moreover, download statistics can vary substantially based on the characteristics of the user interface . Last, a citation implies--but does not require--that the document has been accessed and read. Because an author may cite from the abstract of an article or simply copy a reference from another paper [10, 11], citation data may overstate the extent to which the scientific literature has been consulted.
In evaluating scholars' use of the research literature, it is important to acknowledge the limits of what each study can add to knowledge of the issues. As most scientists are both readers and authors, their interests and priorities may vary with the role they assume at any particular time .
AUTHORSHIP AND USE OF THE SCIENTIFIC LITERATURE BY SCHOLARS IN DEVELOPED NATIONS
Studies based on surveys and interviews
Over the past thirty years, periodic studies of the information-seeking and reading behavior of scientists in the United States have revealed three trends: (1) scientists are reading more articles while spending less time searching and retrieving them; (2) scientists now read from a broader group of journals and extend their reading into the older literature; and (3) scientists have become more reliant on institutional (library) access to journal collections, although they also make use of informal sources such as preprint servers and colleagues [13-21].
Overall, most surveyed researchers indicate that they have adequate access to the scientific literature and that access conditions are generally improving. An international survey of authors conducted in 2004 revealed that 61% of respondents indicated that they had "good" or "excellent" access to the journal literature. Three-quarters (76%) of respondents also felt that access was easier than it was 5 years ago . A similar study of immunologists and microbiologists conducted in 2004 revealed that two-thirds of respondents (67%) reported they had "good" or "excellent" access to the literature . Nearly 84% claimed that access was much better now than it had been 5 years before, and almost all (97%) reported that they were "very up-to-date with the current literature in their area," with less than 35% reporting any need for greater access to the research literature. In a list of 16 potential barriers to higher research productivity, journal access ranked 12th, below everything but greater conference/networking opportunities, better research leadership, more general management training, and clearer legal and ethical frameworks .
Surveying international scientific authors in 2007, Ware found that 69% of respondents reported having "good" or "excellent" access to the literature, a figure that varied by region . Authors in the United States and Canada were most satisfied (85% reported "good" or "excellent" access; 3% reported "poor" access), while those in other countries were significantly less satisfied (53% reported "good" or "excellent"; 15% reported "poor"). In Ware's latest study, conducted in 2010 , 93% of all respondents reported having "very easy" or "fairly easy" access to the journal literature, a finding which varied from 97% for North American respondents to as low as 78% for African respondents.
Ware also surveyed small and medium-sized commercial enterprises in the United Kingdom, including companies involved in pharmaceuticals, chemicals, computing, and medical and precision instruments . More than 70% of respondents claimed that they had "very easy" or "fairly easy" access to the journal literature, and 60% reported that their level of access had gotten better over the past 5 years. Among enterprises with more than 250 employees, 82% reported having easy access to the journal literature. Ware's study used a sample of convenience, however, and only 4% of potential respondents completed the survey.
While greater access to the scientific literature has undoubtedly altered the behavior of scientists as readers, it is not among their main priorities as authors. In deciding where to submit their work, an international survey of scientists revealed that authors were most concerned with each journal's reputation, readership, impact factor, and speed of publication . In contrast, access status and copyright-related issues were ranked last.
Although these large-scale studies are prone to several forms of bias, such as sampling bias and nonresponse bias, they are confirmed by a number of smaller but more rigorous studies of authors' preferences. For example, authors submitting manuscripts to the British Medical Journal reported that impact factor, reputation, readership, speed of publication, and quality of peer review were all major factors in deciding where to submit their work. In contrast, only 13% rated free access as important .
In-depth interviews with authors and other stakeholders reveal similar values and priorities. A series of interviews with faculty at the University of California, Berkeley, revealed that authors were most concerned about the mechanisms that ensure the quality of journal articles and the integrity of the peer-review process. Other considerations, such as the costs of the scholarly publication system, did not have much impact on their work . Although many librarians "strongly perceive a crisis in scholarly communication," most faculty do not, underscoring a fundamental perceptual difference between these two stakeholder groups.
A recent and more extensive study, by Harley and colleagues, explored the values, motivations, and behavior of 160 interviewees at 45 research universities across the United States . The recurring theme in this report is that the scholarly community is conservative, with a firm dedication to disciplinary norms and an unyielding commitment to external peer-review and assessment. There is little room for experimentation with new forms of publication, especially for new academics. In particular, many faculty view author-pays open access publishing with suspicion due to the potential conflict between publication fees and rigorous peer-review. Overall, Harley and colleagues "heard little about a crisis in scholarly communication" . The only faculty who perceived a crisis were some of those in the humanities, who noted that the diminishing output of university presses made it more difficult to publish their work as academic books.
Several months after the Harley report, Schonfeld and Housewright released another report on the perceptions and behavior of faculty with regard to scholarly communication . Their findings, based on a series of longitudinal surveys conducted every three years since 2000, were remarkably consistent with those of the Harley report. With regard to publishing, faculty attitudes are fundamentally conservative and are guided almost entirely by career advancement. Faculty expressed little interest in transforming the scholarly communication system, and across all disciplines, free access to journal content was consistently ranked last among the factors considered by authors when selecting a journal in which to publish. In contrast, the absence of publication fees was ranked as the second most important factor, suggesting, as Schonfeld and Housewright  pointed out, that the author-pays model of open access publishing might be at odds with the attitudes of many faculty. As numerous studies have shown, the primary goal of most faculty is to publish in journals that are widely read by scholars in their field [23, 27, 28, 32]. If transforming the scholarly publishing system is a goal of faculty, that goal is nonetheless eclipsed by issues of career advancement.
Table 1 (online only) presents a summary of the major studies described in this section.
Studies based on unobtrusive methods
Downloads. Usage data compiled from the online transaction logs of Elsevier and Oxford University Press reveal two major trends of the past several years: an increase in the number of journals available at a typical university and an even larger increase in the number of article downloads . Publishers who offer package deals view these data as an indication that they are providing increasing value to the academic community . While these trends suggest the importance of commercial access to the scientific literature, little is known about the effect of free access on readership.
A case study of article downloads for the journal Nucleic Acid Research revealed that moving from a subscription-access model to an open access model resulted in more than twice the number of article downloads (portable document format [PDF] and hypertext markup language [HTML] combined), although most of this increase was attributed to Internet robots (automated applications that index web pages) rather than human intention . Likewise, randomized controlled trials of open access publishing revealed that free access has a significant, independent impact on the number of downloads, although robots account for roughly half of the increase . Articles that were made freely available received about twice as many full-text downloads but correspondingly fewer PDF downloads, suggesting that the primary benefit to the non-subscriber community is in browsing [36-38]. Due to the nature of these studies, which rely on transactional usage logs, it is only possible to make inferential statements about reader behavior. Further investigation is required to determine who is accessing these articles and for what purpose.
Citations. The impact of online and open access on scholars' citation behavior is not entirely clear. There is some dispute over whether increased access has broadened the scope of cited material. Using a complex inferential model, Evans  reported that commercial access to the literature through large online collections and full-text databases has led to a reduction in the scope of the articles that are likely to be cited, with an emphasis on newer articles from a smaller number of journals. McCabe and Snyder refuted these claims, asserting that Evans' model suffered from a methodological flaw . Moreover, Lariviere and colleagues  reached a different conclusion: that citations to the scientific literature are becoming more dispersed over time. Their findings are supported by a number of author surveys [13-21].
Several studies have indicated that free (or open) access to scientific publications leads to significant increases in the number of article citations [42-51]. These studies imply that the demand for access to the scientific literature has not been fully met by current distribution models. Other studies claim that free access is responsible for accelerating the citation process [52-57] or that it may have preferential effects for researchers in developing countries [58, 59].
Most studies investigating the association between access status and citations are based on various forms of unobtrusive, observational analysis. As Craig and colleagues  illustrate in their comprehensive review of the literature, many of these studies suffer from three methodological problems: (1) failure to control for confounding variables (i.e., failure to distinguish clearly between the impact of access status and the effects of related variables); (2) failure to provide more than correlation as evidence of a causal relationship; and (3) inadequate specification of the observation window for the citation process. As a number of critical studies have shown, these issues make it difficult to determine whether free access has a real, independent effect on citation rates [36, 54-57, 60-66]. McCabe and Snyder argue that the large citation effects reported in prior studies are simply artifacts of the researchers' inability to control for important covariates such as time and differences in article quality .
To isolate the effect of free access on article readership and citations, Davis and colleagues conducted several controlled experiments that allowed them to randomly assign free-access status to articles on the websites of various academic journals. In theory, random assignment allows the researchers to control for potential differences at the start of the experiment, including unobserved variables such as article quality, between the treatment and control group. In their first study, involving eleven journals in physiology, they found that open access articles received more article downloads, yet no more citations than subscription articles in the first year after publication . A larger trial involving thirty-six journals in the sciences, social sciences, and humanities demonstrated no citation difference at three years [37, 38].
Overall, the conclusions of Craig and colleagues  are well supported by subsequent work. After controlling statistically or methodologically for confounding effects, there is little evidence that open access status has an independent effect on citation counts. Table 2 (online only) presents a summary of the key papers that examine the impact of free access on citation rates.
AUTHORSHIP AND USE OF THE SCIENTIFIC LITERATURE BY SCHOLARS IN DEVELOPING NATIONS
The high cost of Western scientific journals poses a major barrier to researchers in developing nations. While researchers in North America and Western Europe rely primarily on institutional (library) access to scholarly journals, the situation is different in many developing nations. Researchers in India, for example, rely more heavily on informal access to the scientific literature because their institutions are unable to provide the research literature they require .
Collaborative projects such as HighWire's Free Access to Developing Economies  and multi-publisher programs focusing on disciplines such as agriculture (Access to Global Online Research in Agriculture [AGORA]), health and medicine (Health InterNetwork Access to Research Initiative [HINARI]), and the environment (Online Access to Research in the Environment [OARE]) have attempted to bridge the access gap by providing free or heavily subsidized access to institutions in the world's poorest regions . Several studies have attempted to ascertain whether researchers in developing countries have benefited from free access by determining whether free access has influenced their authorship and citation behavior. In her dissertation, Ross  evaluated the effectiveness of the HINARI and AGORA programs by analyzing the citations to participating journals before and after the programs were initiated. Her results were mixed: In some regions, citations to the participating journals increased, while in others, they decreased. No systematic geographical pattern was reported.
An analysis of open access and subscription journals in the field of biology revealed that authors in developing countries are no more likely than authors in developed countries to cite or to publish in open access journals . Likewise, a study of conservation biology journals and book chapters revealed that authors in developing countries do not cite freely available articles at a higher rate than articles requiring subscriptions . Both these studies were based on small samples with high variability, so they might not have the statistical power to detect small effects. However, the absence of strong effects in both these studies suggests that the impact of free access on developing-country publishing or citation patterns, if it indeed exists, is likely to be small.
A larger, comparative study of Swiss and Indian scholars revealed that articles written by Indian researchers had shorter reference lists and were more likely to cite articles from open access journals . The effect sizes reported by Gaule were small, though. Controlling for the publication source, Indian reference lists were 6% (less than 2 references) shorter and contained just 0.16 more citations to open access articles. Considering that Indian research institutions have far poorer access to the published literature than their Swiss counterparts, the impact of free access appears to be modest. Supplementing his bibliometric analysis with a follow-up survey, Gaule  found that Indian scholars routinely requested copies of articles from the authors of the studies and from their colleagues at better-endowed institutions. Some respondents admitted asking former students who had moved to North American or European institutions for help with access to the journal literature.
On a global scale, Evans and Reimer  reported that free access to the published literature had a small but significant effect on citation behavior, especially for authors in developing nations. However, McCabe and Snyder concluded that the apparent geographical differences in citation rates were an artifact of the methods Evans and Reimer used. Using a similar dataset, McCabe and Snyder found no regional differences in citation rates . While the developing world benefits from online access to the scientific literature, McCabe and Snyder report, that gain is no greater than the benefit derived by scholars in the United States and other English-speaking Western countries.
The greatest reported impact of free online access was mentioned in a press release from Research4Life . The authors claimed that the total annual output of peer-reviewed research articles increased substantially among countries that participated in the HINARI, AGORA, and OARE programs. Unfortunately, the press release did not provide information on the methods used to reach that conclusion, and no attempt was made to control for potentially important confounding factors, such as country wealth, national expenditures on research and development, number of active scientists, emergence of research centers in high-impact fields such as medicine, or improvements in library and information technology infrastructures. The authors also provided no data on the number of articles published in each country, as even modest increases in article publication in countries with historically low output can result in high percentage increases. In the absence of more detailed information, the Research4Life results should be considered speculative at this point.
IMPACT OF FREE ACCESS ON CLINICAL DECISION MAKING
To date, only one study has evaluated the clinical implications of free access to the medical literature. In a pair of related experiments, Hardisty and Haaga  investigated whether increased access to relevant journal articles had an impact on the use of the articles in clinical psychotherapy. Participating mental health professionals were provided with 1 of 4 access conditions: (1) no mention of the relevant article, (2) a citation to the article without a hyperlink, (3) a citation with a link to the article (which cost $11.95 for all but registered subscribers), or (4) a citation with a link to a free copy of the article. After 1 week, participants read a vignette on the topic covered by the article and were asked about their recommendations for a medical intervention. In both studies, participants in group 4 were most likely to report having read the article. However, in only 1 study did reading the article translate into making a recommendation consistent with the information it presented. These results indicate that while free access increases the likelihood of downloading and reading research articles, it does not necessarily influence clinical practice. Further research is necessary, however, because Hardisty and Haaga's study represents just one clinical setting and one of several possible evaluation methods.
USE OF THE BIOMEDICAL LITERATURE BY THE GENERAL PUBLIC
The empowerment of health care consumers through universal access to original research has been cited as a key benefit of free access to the scientific literature . However, relatively little is known about the use of scientific literature by the general public. Anecdotal descriptions are not uncommon--for instance, patients bringing medical literature they found online into the doctor's office--but relatively few studies have investigated how the public uses the primary research literature rather than consumer-focused websites, blogs, and discussion lists.
It is clear, however, that Americans are actively seeking health information online. Periodic telephone surveys of American adults conducted by the Pew Research Center reveal that the percentage of adults who look for health information online increased substantially between 2002 and 2008 . By 2006, 80% of American Internet users had searched for information on at least 1 health-related topic . That figure, unchanged in 2010, varies with income, race, and other demographic and socioeconomic characteristics . For those with a disability or chronic disease, the percentage is even higher, about 86% . Those with chronic conditions are also especially likely to report that online searching has affected their treatment decisions and their interactions with doctors. Respondents who experienced recent health crises are also more likely to get a second opinion or to ask their doctor new questions based on their online research, and, not surprisingly, individuals with home broadband access are more than twice as likely as dial-up users to conduct health research online . According to the Pew telephone surveys, most Internet users begin their research on health or medical topics by using a general search engine such as Google rather than a health-related website . These results are confirmed by naturalistic observational studies of how laypersons search for online health information in an experimental setting [79-81].
Distinguishing primary literature from secondary and user-generated sources
The Pew telephone surveys list many sources of medical information including websites, blogs, commentary, and podcasts, but they do not ask respondents to distinguish between scholarly and non-scholarly resources [74, 82]. In particular, they make no specific mention of journals or scientific articles as sources of medical information, although they do distinguish "Internet" from "printed reference material" , as well as identifying cell phones and mobile applications . Likewise, the Health Information National Trends Survey (HINTS) of the National Cancer Institute asks several questions about sources of health information, but the available responses represent a potentially confusing set of information providers, media, and delivery mechanisms . For example, question HC02 asks, "The most recent time you looked for information about heath or medical topics, where did you go first?" and offers response categories such as "Internet" (61.0%); "Doctor or health care provider" (13.9%); "Books" (8.4%); "Brochures, pamphlets, etc." (3.8%); and "Magazines" (3.4%). It is difficult to discern what the researcher is implying--or, indeed, what the survey respondent might be thinking--when asked about Internet use. Magazines, books, brochures, and health care providers can all be accessed via the Internet, just as doctors and other health care providers communicate in person, via the Internet, and through books, brochures, and magazines. A more recent (2010) survey of the health-seeking behavior of adults separated "Internet" from "Media," the latter consisting of newspapers, magazines, and television . Neither of these studies distinguished between the primary medical literature (e.g., scholarly journals) and popular health magazines.
Most medical and health-related websites suffer from significant problems in terms of accuracy, bias, and completeness [86, 87]. Nongovernmental websites are especially prone to these problems . While laypersons claim that they use a number of criteria in evaluating the credibility of medical websites, few of them actually check the authority of web resources or are able to later recall the sources of their information . Indeed, just 15% of telephone survey respondents claimed that they "always" checked the source and date of the information they found online, and 10% claimed that they did so "most of the time" .
Evaluating websites retrieved through a series of online searches for medical terms, Laurent and colleagues found that the user-generated online encyclopedia, Wikipedia, ranked higher in the search results than professional sites such as MedlinePlus, which is maintained by the National Library of Medicine and the National Institutes of Health . Indeed, Wikipedia appeared on the first page, among the first ten results, for the overwhelming majority of medical keyword searches conducted in Google, Google UK, Yahoo, and MSN. Despite significant errors of omission and the absence of source attribution , Wikipedia is a prominent source of online health information.
No study has systematically evaluated the extent to which the general public makes use of the primary medical literature rather than secondary and user-generated sources such as Wikipedia and WebMD. Nonetheless, the available evidence shows that "the Internet" (however survey respondents might define it) is the primary source of health-related information for the American public and that typical Internet users are far more likely to encounter secondary sources of health information than the primary health sciences literature. Research has shown that the quality of consumer health information can be improved through better integration of the primary literature into online health resources and through public involvement in the development of such resources. However, even these efforts involve the use of tools and interfaces that repackage, summarize, and simplify the results of medical research-not on the unmediated reading of the scientific literature by the general public [91-93]. Overall, the published evidence does not indicate how (or whether) free access to the scientific literature influences consumers' reading or behavior.
SUMMARY AND DISCUSSION
Access to the scientific literature is not a serious concern of most scholars in developed nations, and most researchers feel that their access to the literature is steadily improving. While free access leads to greater readership, its overall impact on citations is still under investigation. The large access-citation effects found in many early studies appear to be artifacts of improper analysis and not the result of a causal relationship.
Current research reveals no evidence of unmet demand for the primary medical or health sciences literature among the general public. This does not necessarily reflect the absence of unmet demand; it may simply indicate that the question has not been addressed adequately. Likewise, almost no studies have evaluated whether free access to the scientific literature has had an impact on the use of scientific information in non-research contexts such as teaching, medical practice, industry, and government.
Sources of bias in the research literature
Most studies on the use of the primary scientific literature reflect the opinions and behaviors of those who are well integrated into the system of scholarly communication. This might be regarded as a form of bias because the true population of interest includes not just those who currently rely on the research literature, but those who might make good use of it if they were more fully aware of its utility. Arguably, the greatest value of open access journals and archives is their potential to make scholarly information available to those who consume, but do not contribute to, the scientific literature. At present, however, there is little evidence that this potential has been realized. Admittedly, the existence of a resource (such as a library collection or a body of open access literature) has value independent of the number of downloads, citations, or other indicators of use: option value (the value of the personal right to use the resource in the future), existence value (the value derived from the knowledge that the resource is available for others' use), and bequest value (the value of making the resource available to future generations of scholars) . However, these kinds of utility are difficult to measure; are not as readily apparent to authors, readers, and publishers; and are of less immediate value than the indicators of use that drive the present-day scholarly communication system.
Impediments to broader access
The studies presented here suggest that publication fees are perhaps the greatest impediment to broader participation in open access initiatives. While fewer than 30% of open access journals charge publication fees, those journals represent half of all open access articles . Moreover, the proportion is much higher for particular disciplines and publisher types. For example, publication fees were levied for approximately 69% of the open access biology articles published in 2008/09 (all publisher types combined) and for 76% of the commercially published open access articles in 6 subject areas . At the same time, there is clear evidence that faculty generally do not like publication fees , and many fear that the pay-to-publish model may compromise the integrity of peer review . It is important to realize that individuals' opinions of general publishing practices may be contrary to their attitudes about particular journals. For instance, PLoS Biology and PLoS Medicine both charge relatively high publication fees, but neither seems to have trouble attracting submissions. The business model adopted by these 2 journals may or may not be transferable to other journals or publishers, but it does demonstrate that at least some free-access journals have the potential to transcend the limitations noted here.
Alternative routes of access to the scientific literature
Most research on access to the scientific literature assumes a traditional and hierarchical flow of information from the publisher to the reader, with the library often serving as an intermediary between the two. Very little has been done to investigate alternative routes of access to the scientific literature. If consumers of the scientific literature operate in the same way as consumers of cultural media (music and video, for example), studies that focus on publisher-initiated communication might overlook important components of the scholarly communication system. While interlibrary lending is one such component, the direct transfer of documents among colleagues may represent an even larger flow of information. Gaule's  study of access to scientific information in India suggests that informal peer-to-peer sharing is very common in countries with a history of poor access to the scientific literature. For authors, the practice of fulfilling reprint requests by physical post has largely been replaced by transmtting articles by email or by directing readers to publicly accessible online archives or the public Internet .
A 2009 mandate of the US National Institutes of
Health requires researchers in receipt of federal funding to deposit their final, peer-reviewed manuscripts in PubMed Central . Several research universities have also set forth their own self-archiving requirements . Open access archives such as PubMed Central may attenuate existing access inequalities, but only if authors' manuscripts are adequate substitutes for the published record. This requires, among other things, that manuscripts are posted online in a timely fashion, made readily discoverable by readers (through indexing or other mechanisms), and preserved for future use.
As noted earlier, there is a clear need for empirical research dealing with the impact of free access on the use of the scientific literature by the general public and by communities that consume, but do not contribute to, the scholarly literature. It is also important to gain a better understanding of the constructs and measures that are commonly used in studies of scholarly publishing. For instance, to what extent do downloads and citations correspond to the careful reading of articles?
Research on free access might also be improved through more careful attention to the various forms of bias that persist in both surveys and observational studies. For instance, studies of the impact of free access on citation rates have been hindered by a number of methodological problems including selection bias and incomplete model specification (e.g., failure to control for all relevant confounding variables). Studies of free access are likely to benefit from a greater understanding of these problems and a stronger consensus on the most effective ways of dealing with them.
Finally, further research should investigate the extent to which scholars rely on informal sharing of the scientific literature. This kind of sharing is often poorly documented, since individuals are not required to track and report document transactions to the publisher, nor are institutional repositories, subject repositories, public websites, or peer-to-peer file sharing programs. By relying entirely on publisher-provided usage data, researchers may under estimate the extent to which scholarly works are disseminated through such secondary and tertiary pathways. It is possible that these alternate methods of access help to attenuate the current inequalities in formal access to the scholarly literature.
* Researchers in the sciences do not see access to the scientific literature as an especially important problem.
* Authors consider factors such as journal reputation and the absence of publication fees when deciding where to submit their work. In contrast, free access is not a significant factor in their submission decisions.
* While open access has the potential to expand the authorship and readership of the scientific literature, that potential has not yet been realized.
* Librarians who encourage scientists to publish in open access journals should be aware of the authors' priorities and perspectives. Authors in the sciences tend to focus on citation impact, reputation, and accessibility to a specialized readership-not breadth of readership, copyright, or access status.
* Journal publishers that charge publication fees may want to consider alternative sources of revenue. Authors' resistance to publication fees is a major barrier to greater participation in open access initiatives.
Received December 2010; accepted February 2011
[1.] Open Access Now. (Mis)leading open access myths [Internet]. BioMed Central [cited 29 Nov 2010]. <http://www .biomedcentral.com / openaccess /inquiry/myths/?myth=all>.
[2.] Willinsky J. The access principle: the case for open access to research and scholarship. Cambridge, MA: MIT Press; 2006.
[3.] Association of Research Libraries. Create change [Internet]. Washington, DC: Scholarly Publishing and Academic Resources Coalition; 2002 [cited 11 Feb 2011]. <http://www .arl.org/createchange/bm~doc/createchange2003.pdf>.
[4.] Thatcher SG. The crisis in scholarly communication. Chron Higher Educ. 1995 Mar 3;41(25):B1.
[5.] English R. Scholarly communication and the academy: the importance of the ACRL initiative. Portal-Libr Acad. 2003 Apr;3(2):337-40.
[6.] Guedon JC. In Oldenburg's long shadow: librarians, research scientists, publishers, and the control of scientific publishing. In: Baker SK, ed. Creating the digital future: proceedings of the 138th annual meeting. Toronto, ON, Canada: Association of Research Libraries; 2001. p. 70.
[7.] Lewis-Beck M, Bryman A, Liao TF. Encyclopedia of social science research methods. Thousand Oaks, CA: Sage Publications; 2003. p. 1528.
[8.] Lavrakas PJ. Encyclopedia of survey research methods. Thousand Oaks, CA: Sage Publications; 2008. p. 1072.
[9.] Davis PM, Price JS. Ejournal interface can influence usage statistics: implications for libraries, publishers, and Project COUNTER. J Am Soc Inf Sci Technol. 2006 Jul;57(9):1243-8. DOI: 10.1002/asi.20405.
[10.] Simkin MV, Roychowdhury VP. A mathematical theory of citing. J Am Soc Inf Sci Technol. 2007 Sep;58(11):1661-73. DOI: 10.1002/asi.20653.
[11.] Broadus RN. An investigation of the validity of bibliographic citations. J Am Soc Inf Sci. 1983 Mar;34(2): 132-5. DOI: 10.1002/asi.4630340206.
[12.] Mabe MA, Amin M. Dr. Jekyll and Dr. Hyde: author-reader asymmetries in scholarly publishing. ASLIB Proc. 2002; 54(3): 149-57. DOI: 10.1108/00012530210441692.
[13.] Tenopir C, King DW. Chapter 7, Readership of scientific scholarly journals. In: Toward electronic journals: realities for scientists, librarians, and publishers. Washington, DC: Special Libraries Association; 2000.
[14.] Tenopir C, King DW. Reading behaviour and electronic journals. Learn Publ. 2002 Oct;15(4):259-65. DOI: 10.1087/ 095315102760319215.
[15.] Tenopir C, King DW. Chapter 8, Information-seeking and readership patterns. In: Toward electronic journals: realities for scientists, librarians, and publishers. Washington, DC: Special Libraries Association; 2000.
[16.] King DW, Tenopir C. Using and reading scholarly literature. Annu Rev Inform Sci. 1999;34:423-77.
[17.] Tenopir C, King DW, Boyce P, Grayson M, Zhang Y, Ebuen M. Patterns of journal use by scientists through three evolutionary phases. D-Lib Mag. 2003 May;9(5)
[18.] King DW, Tenopir C, Montgomery CH, Aerni SE. Patterns of journal use by faculty at three diverse universities. D-Lib Mag. 2003 Oct;9(10)
[19.] Tenopir C, King DW. Electronic journals and changes in scholarly article seeking and reading patterns. D-Lib Mag. 2008 Nov;14(11/12)
[20.] Tenopir C, King DW, Edwards S, Wu L. Electronic journals and changes in scholarly article seeking and reading patterns. ASLIB Proc. 2009;61(1):5-32. DOI: 10.1108/00012530910932267.
[21.] King DW, Tenopir C, Choemprayong S, Wu L. Scholarly journal information-seeking and reading patterns of faculty at five US universities. Learn Publ. 2009 Apr;22(2):126-44. DOI: 10.1087/2009208.
[22.] Rowlands I, Nicholas D, Huntington P. Scholarly communication in the digital environment: what do authors want? Learn Publ. 2004 Oct;17(4):261-73.
[23.] Rowlands I, Olivieri R. Journals and scientific productivity: a case study in immunology and microbiology [Internet]. London, UK: Publishing Research Consortium; 2006 [cited 28 Mar 2011]. <http://www.publishingresearch .net/documents/Rowland_Olivieri_summary_paper.pdf>.
[24.] Ware M. Peer review in scholarly journals: perspectives of the scholarly community-an international study [Internet]. Bristol, UK: Publishing Research Consortium; 2007 [cited 28 Mar 2011]. <http://www.publishingresearch.net /documents/PeerReviewFullPRCReport-final.pdf>.
[25.] Ware M. Access vs. importance: a global study assessing the importance of and ease of access to professional and academic information: phase I results [Internet]. Bristol, UK: Publishing Research Consortium; 2010 [cited 28 Mar 2011]. <http://www .publishingresearch.net/documents/PRCAccessvsImportance GlobalNov2010_000.pdf>.
[26.] Ware M. Access by UK small and medium-sized enterprises to professional and academic information [Internet]. Bristol, UK: Publishing Research Consortium; 2009 [cited 28 Mar 2011]. <http://www.publishingresearch .net/documents/SMEAccessResearchReport.pdf>.
[27.] Rowlands I, Nicholas D. New journal publishing models: an international survey of senior researchers [Internet]. London, UK: CIBER; 2005 [cited 28 Mar 2011]. <http:// www.ucl.ac.uk/ciber/ciber_2005_survey_final.pdf>.
[28.] Schroter S, Tite L, Smith R. Perceptions of open access publishing: interviews with journal authors. BMJ. 2005 Apr 2; 330 (7494):756. DOI: 10.1136/bmj.38359.695220.82.
[29.] King CJ, Harley D, Earl-Novell S, Arter J, Lawrence S, Perciali I. Scholarly communication: academic values and sustainable models [Internet]. Berkeley, CA: Center for Studies in Higher Education, University of California, Berkeley; 2006 [cited 28 Mar 2011]. <http://cshe.berkeley .edu/publications/docs/scholarlycomm_report.pdf>.
[30.] Harley D, Acord SK, Earl-Novell S, Lawrence S, King CJ. Assessing the future landscape of scholarly communication: an exploration of faculty values and needs in seven disciplines [Internet]. Berkeley, CA: Center for Studies in Higher Education, UC Berkeley; 2010 [cited 28 Mar 2011]. <http://www.escholarship.org/uc/item/15x7385g>.
[31.] Schonfeld RC, Housewright R. Faculty survey 2009: key strategic insights for libraries, publishers, and societies [Internet]. New York, NY: Ithaka S+R; 2010 [cited 28 Mar 2011]. <http://www.ithaka.org/ithaka-s-r/research /faculty-surveys-2000-2009/faculty-survey-2009>.
[32.] Schroter S, Tite L. Open access publishing and author-pays business models: a survey of authors' knowledge and perceptions. J Roy Soc Med. 2006 Mar;99(3):141-8. DOI: 10.1258/jrsm.99.3.141.
[33.] Research Information Network. E-journals: their use, value and impact [Internet]. The Network; 2009 [cited 28 Mar 2011]. <http://www.rin.ac.uk/files/E-journals_use _value_impact_Report_April2009.pdf>.
[34.] UK House of Commons. Scientific publications [uncorrected transcript of oral evidence]. Science and Technology Committee; 2004.
[35.] Nicholas D, Huntington P, Jamali HR. Open access in context: a user study. J Doc. 2007;63(6):853-78. DOI: 10.1108/00220410710836394.
[36.] Davis PM, Lewenstein BV, Simon DH, Booth JG, Connolly MJL. Open access publishing, article downloads and citations: randomised controlled trial. BMJ. 2008 Jul 31; 337: a568. DOI: 10.1136/bmj.a568.
[37.] Davis PM. Open access, readership, citations: a randomized controlled trial of scientific journal publishing. FASEB J. 2011 Jul;25(7), DOI: 10.1096/fj.11-183988.
[38.] Davis PM. Does open access lead to increased readership and citations? a randomized controlled trial of articles published in APS journals. Physiologist. 2010 Dec;53(6): 197-201.
[39.] Evans JA. Electronic publication and the narrowing of science and scholarship. Science. 2008 Jul 18;321(5887): 395-9. DOI: 10.1126/science.1150473.
[40.] McCabe MJ, Snyder CM. Did online access to journals change the economics literature? SSRN working paper, 2011 [Internet]. Social Science Electronic Publishing [cited 28 Mar 2011]. <http://www.ssrn.com/abstract51746243>.
[41.] Lariviere V, Gingras Y, Archambault E. The decline in the concentration of citations, 1900-2007. J Am Soc Inf Sci Technol. 2009 Apr;60(4):858-62. DOI: 10.1002/asi.21011.
[42.] Lawrence S. Free online availability substantially increases a paper's impact. Nature. 2001 May 31;411(6837): 521. DOI: 10.1038/35079151.
[43.] Antelman K. Do open-access articles have a greater research impact? Coll Res Libr. 2004 Sep;65(5):372-82.
[44.] Schwarz GJ, Kennicutt RCJ. Demographic and citation trends in Astrophysical Journal papers and preprints. Bull Am Astron Soc. 2004;36:1654-63.
[45.] Harnad S, Brody T. Comparing the impact of open access (OA) vs. non-OA articles in the same journals. D-Lib Mag. 2004 Jun;10(6)
[46.] Metcalfe TS. The rise and citation impact of astro-ph in major journals. Bull Am Astron Soc. 2005;37:555-7.
[47.] Metcalfe TS. The citation impact of digital preprint archives for solar physics papers. Sol Phys. 2006;239:549-53.
[48.] Norris M, Oppenheim C, Rowland F. The citation advantage of open-access articles. J Am Soc Inf Sci Technol. 2008 Oct;59(12):1963-72. DOI: 10.1002/asi.20898.
[49.] Gargouri Y, Hajjem C, Lariviere V, Gingras Y, Carr L, Brody T, Harnad S. Self-selected or mandated, open access increases citation impact for higher quality research. PLoS ONE. 2010 18 Oct;5(10):e13663. DOI: 10.1371/journal.pone .0013636.
[50.] Hajjem C, Harnad S, Gingras Y. Ten-year cross-disciplinary comparison of the growth of open access and how it increases research citation impact. IEEE Data Engineering Bulletin. 2005;28(4):39-47.
[51.] Gentil-Beccot A, Mele S, Brooks TC. Citing and reading behaviours in high-energy physics. Scientometrics. 2010; 84(2):345-55. DOI: 10.1007/s11192-009-0111-1.
[52.] Eysenbach G. Citation advantage of open access articles. PLoS Biol. 2006 May;4(5):e157. DOI: 10.1371/journal .pbio.0040157.
[53.] ISI. The impact of open access journals: a citation study from Thomson ISI [Internet]. 19 Apr 2004 [cited 28 Mar 2011]. <http://www.thomsonscientific.jp/event/oal /impact-oa-journals.pdf>.
[54.] Kurtz MJ, Eichhorn G, Accomazzi A, Grant C, Demleitner M, Henneken E, Murray SS. The effect of use and access on citations. Inform Process Manag. 2005; 41:1395-402. DOI: 10.1016/j.ipm.2005.03.010.
[55.] Moed HF. The effect of 'open access' upon citation impact: an analysis of ArXiv's condensed matter section. J Am Soc Inf Sci Technol. 2007 Nov;58(13):2047-54. DOI: 10.1002/asi.20663.
[56.] Kurtz MJ, Henneken EA. Open access does not increase citations for research articles from The Astrophysical Journal [Internet]. Cambridge, MA: Harvard-Smithsonian Center for Astrophysics; 2007 [cited 28 Mar 2011]. <http:// www.arxiv.org/abs/0709.0896>.
[57.] Henneken EA, Kurtz MJ, Eichhorn G, Accomazzi A, Grant C, Thompson D, Murray SS. Effect of e-printing on citation rates in astronomy and physics. J Electron Publishing. 2006;9(2).
[58.] Evans JA, Reimer J. Open access and global participation in science. Science. 2009 20 Feb;323(5917):1025. DOI: 10.1126/ science.1154562.
[59.] Gaule; P. Access to scientific literature in India. J Am Soc Inf Sci Technol. 2009 Dec;12(8):2548-53. DOI: 10.1002/ asi.21195.
[60.] Craig ID, Plume AM, McVeigh ME, Pringle J, Amin M. Do open access articles have greater citation impact? a critical review of the literature. J Informetr. 2007;1(3):239-48. DOI: 10.1016/j.joi.2007.04.001.
[61.] Davis PM. Author-choice open access publishing in the biological and medical literature: a citation analysis. J Am Soc Inf Sci Technol. 2009;60(1):3-8. DOI: 10.1002/asi.20965.
[62.] Gaule; P, Maystre N. Getting cited: does open access help?: CEMI working paper 2008-007, 2008 [Internet]. [cited 28 Mar 2011]. < http://papers.ssrn.com/sol3/papers .cfm?abstract_id=1427763>.
[63.] Lansingh VC, Carter MJ. Does open access in ophthalmology affect how articles are subsequently cited in research? Ophthalmology. 2009 Aug;116(8):1425-31. DOI: 10.1016/j.ophtha.2008.12.052.
[64.] Calver MC, Bradley JS. Patterns of citations of open access and non-open access conservation biology journal papers and book chapters. Conserv Biol. 2010 Jun;24(3): 872-80. DOI: 10.1111/j.1523-1739.2010.01509.x.
[65.] Davis PM. Do open-access articles really have a greater research impact? Coll Res Libr. 2006 Mar;66(2):103-5.
[66.] Davis PM, Fromerth MJ. Does the arXiv lead to higher citations and reduced publisher downloads for mathematics articles? Scientometrics. 2007;71(2):203-15. DOI: 10.1007/ s11192-007-1661-8.
[67.] HighWire Press. Free access to developing economies [Internet]. HighWire Press [cited 11 Nov 2010]. <http:// highwire.stanford.edu/lists/devecon.dtl>.
[68.] Research4Life. Research4Life: HINARI, AGORA, OARE [Internet]. 2002 [cited 22 Apr 2010] <http://www.research4life .org>.
[69.] Ross SVT. The scholarly use of journals offered through the Health InterNetwork Access to Research Initiative (HINARI) and Access to Global Online Research in Agriculture (AGORA) programs as suggested by the journal-citing patterns of authors in the least-developed nations [Internet]. Tallahassee, FL: Florida State University; 2008 [cited 28 Mar 2011]. <http://etd.lib.fsu.edu/theses/available/etd-08082008 -171628/unrestricted/RossSDissertation.pdf>.
[70.] Frandsen TF. Attracted to open access journals: a bibliometric author analysis in the field of biology. J Doc. 2009;65(1):58-82. DOI: 10.1108/00220410910926121.
[71.] Research4Life. Research output in developing countries reveals 194% increase in five years [Internet]. Research4Life; 2009 [cited 28 Mar 2011]. <http://www.who.int/hinari /Increase_in_developing_country_research_output.pdf>.
[72.] Hardisty DJ, Haaga DAF. Diffusion of treatment research: does open access matter? J Clin Psychol. 2008;64(7):821-39. DOI: 10.1002/jclp.20492.
[73.] Eysenbach G. The open access advantage. J Med Internet Res. 2006 Apr-Jun;8(2):e8. DOI: 10.2196/jmir.8.2.e8.
[74.] Fox S, Jones S. The social life of health information [Internet]. Washington, DC: Pew Internet & American Life Project; 2009 [cited 28 Mar 2011]. <http://www.pewinternet .org/~/media/ /Files/Reports/2009/PIP_Health_2009.pdf>.
[75.] Fox S. Online health search 2006 [Internet]. Washington, DC: Pew Internet & American Life Project; 2006 [cited 28 Mar 2011]. <http://www.pewinternet.org/,/media //Files/Reports/2006/PIP_Online_Health_2006.pdf.pdf>.
[76.] Fox S. Health topics: 80% of Internet users look for health information online [Internet]. Washington, DC: Pew Internet & American Life Project; 2011 [cited 28 Mar 2011]. <http:// www.pewinternet.org/Reports/2011/HealthTopics.aspx>.
[77.] Fox S. E-patients with a disability or chronic disease [Internet]. Washington, DC: Pew Internet & American Life Project; 2006 [cited 28 Mar 2011]. <http://www.pewinternet.org/Reports /2007/Epatients-With-a-Disability-or-Chronic-Disease.aspx>.
[78.] Fox S. The engaged e-patient population [Internet]. Washington, DC: Pew Internet & American Life Project; 2008 [cited 28 Mar 2011]. <http://www.pewinternet.org /Reports/2008/The-Engaged-Epatient-Population.aspx>.
[79.] Eysenbach G, Kohler C. How do consumers search for and appraise health information on the World Wide Web? qualitative study using focus groups, usability tests, and in depth interviews. BMJ. 2002 Mar 9;324(7337):573-7. DOI: 10.1136/bmj.324.7337.573.
[80.] Mager A. Mediated health: sociotechnical practices of providing and using online health information. New Media Soc. 2009 Nov;11(7):1123-42. DOI: 10.1177/1461444809341700.
[81.] Toms EG, Latter C. How consumers search for health information. Health Inform J. 2007 Sep;13(3):223-35. DOI: 10.1177/1460458207079901.
[82.] Fox S. Cancer 2.0 [Internet]. Washington, DC: Pew Internet & American Life Project; 2010 [cited 28 Mar 2011]. <http://www.pewrsr.ch/Cancer20>.
[83.] Fox S. Mobile health 2010 [Internet]. Washington, DC: Pew Internet & American Life Project; 2010 [cited 28 Mar 2011]. <http://www.pewinternet.org/Reports/2010 /Mobile-Health-2010.aspx>.
[84.] National Cancer Institute. Health information national trends survey (HINTS) [Internet]. Washington, DC: The Institute; 2007 [cited 10 Nov 2010]. <http://hints.cancer .gov/questions/index.jsp>.
[85.] Couper MP, Singer E, Levin CA, Fowler FJ, Fagerlin A, Zikmund-Fisher BJ. Use of the Internet and ratings of information sources for medical decisions: results from the DECISIONS survey. Med Decis Making. 2010 Sep/Oct;30(5 suppl):106S-14S. DOI: 10.1177/0272989x10377661.
[86.] Eysenbach G, Powell J, Kuss O, Sa E-R. Empirical studies assessing the quality of health information for consumers on the World Wide Web: a systematic review. JAMA. 2002 May 22;287(20):2691-700. DOI: 10.1001/ jama.287.20.2691
[87.] Clauson KA, Polen HH, Boulos MNK, Dzenowagis JH. Scope, completeness, and accuracy of drug information in Wikipedia. Ann Pharmacother. 2008 Dec;42(12):1814-21. DOI: 10.1345/aph.1L474.
[88.] Scullard P, Peacock C, Davies P. Googling children's health: reliability of medical advice on the Internet. Arch Dis Child. 2010 Aug;95(8):580-2. DOI: 10.1136/adc.2009.168856.
[89.] Fox S. Online health search 2006 [Internet]. Washington, DC: Pew Internet & American Life Project; 2006 [cited 28 Mar 2011]. <http://www.pewinternet.org/,/media //Files/Reports/2006/PIP_Online_Health_2006.pdf.pdf>.
[90.] Laurent MR, Vickers TJ. Seeking health information online: does Wikipedia matter? J Am Med Inform Assoc. 2009 Jul;16(4):471-9. DOI: 10.1197/jamia.M3059.
[91.] Wale J, Colombo C, Belizan M, Nadel J. International health consumers in the Cochrane Collaboration: fifteen years on. J Ambul Care Manage. 2010 Jul/Sep;33(3):182-9. DOI: 10.1097/JAC.0b013e3181e62c15.
[92.] White PJ. Evidence-based medicine for consumers: a role for the Cochrane Collaboration. J Med Libr Assoc. 2002 Apr;90(2):218-22.
[93.] Colledge A, Car J, Donnelly A, Majeed A. Health information for patients: time to look beyond patient information leaflets. J R Soc Med. 2008 Sep;101(9):447-53. DOI: 10.1258/jrsm.2008.080149.
[94.] Krutilla JV. Conservation reconsidered. Am Econ Rev. 1967;57:777-86.
[95.] Walters WH, Linvill A. Characteristics of open access journals in six subject areas. Coll Res Libr. 2011 (in press).
[96.] Wren JD. Open access and openly accessible: a study of scientific publications shared via the Internet. BMJ. 2005 Apr 12;330(7500). DOI: 10.1136/bmj.38422.611736.E0.
[97.] National Institutes of Health. The Omnibus Appropriations Act of 2009 makes the NIH public access policy permanent [Internet]. Bethesda, MD: The Institutes; 2009 [cited 23 Mar 2009]. <http://www.grants.nih.gov/grants /guide/notice-files/NOT-OD-09-071.html>.
[98.] Howard J. Digital repositories foment a quiet revolution in scholarship. Chron Higher Educ. 2010 Jun 13.
Philip M. Davis, PhD; William H. Walters, PhD, FCLIP
Philip M. Davis, PhD * (corresponding author), email@example.com, Postdoctoral Associate, Department of Communication, 301 Kennedy Hall, Cornell University, Ithaca, NY, 14853; William H. Walters, PhD, FCLIP, firstname.lastname@example.org, Dean of Library Services and Associate Professor of Social Sciences, Bowman Library, Menlo College, 1000 El Camino Real, Atherton, CA 94027
* This author is supported by a grant from the Andrew W. Mellon Foundation, Scholarly Communications and Information Technology section.
Table 1 Key interview and survey-based papers on the importance of free access to the scientific literature Authors Study design Survey population Rowlands et Web-based International sample of corresponding al., 2004  survey authors extracted from ISI author database. Survey conducted in 2005. Rowlands Web-based International sample of corresponding and Nicholas, survey authors extracted from ISI author 2005  database. Survey conducted in 2005. King et al., In-person 49 interviewees (31 faculty, 5 2006  interviews librarians, 2 campus/level administrators, 11 steering committee members). Faculty selected from 5 departments. 22/31 faculty are/were editors of scholarly journals. Interviews conducted in 2005 and 2006. Rowlands Web-based Reanalysis of 2 prior author surveys and Olivieri, survey and undertaken in 2004 and 2005. 2006  interviews Immunologists and microbiologists. (phone, in- Sample details not clear. person) Ware, 2007 Web-based Authors, reviewers, and editors of  survey scientific journals. Data from ISI and journal websites. Survey conducted in 2007. Gaule, 2009 Web-based India-based corresponding authors who  survey had published in 2007. Data from ISI author database. Survey conducted in 2008. Ware, 2009 Web-based Corporate users of scholarly  survey information. Identified through subscription lists of trade magazines; corporate authors of science, technology, medicine (STM) articles; and purchasers of individual journal articles (PPV). Survey conducted in 2009. Harley et al., In-person 160 interviewees and focus group 2010  interviews members selected by snowball sampling from 7 academic disciplines, including administrators, librarians, consultants, and publishers. Survey conducted from 2005-2009. Schonfeld Paper-based US college and university faculty. and mail survey Survey last conducted in 2009. Housewright, 2010  Ware, 2010 Web-based International sample of corresponding  survey authors, extracted from Scopus author database. Survey conducted in 2010. Authors Response rate Key findings Rowlands et 3,787 of 61% reported having "good" or al., 2004  107,500 "excellent" access to the journal invitations literature. 76% reported that access (3.5%) is improving over time. Rowlands 5,513 of Top concerns of authors selecting a and Nicholas, 76,790 journal in which to publish: 2005  invitations reputation, readership, and impact (7.2%) factor. Least important concerns: permission to post a copy of one's article, and retention of copyright. King et al., NA Faculty perceptions and behavior are 2006  defined by disciplinary norms and the academic reward structure. Faculty are concerned primarily with the quality of published work (e.g., peer review), not with cost or affordability. Disjoint between perceptions of faculty and librarians. Rowlands Sample of 67% reported having "good" or and Olivieri, 3,695; "excellent" access to the journal 2006  subsample of literature. 84% reported that access 92 is improving over time. Ware, 2007 3,040 of 69% reported having "good" or  39,232 (7.7%) "excellent" access to the journal literature. Highest for United States and Canada (85%) and Australasia (84%); lower for the rest of the world (53%). Gaule, 2009 348 of 2,212 Article requests from informal sources  (16.0%) (colleagues, authors) are common. Most article requests are honored. Ware, 2009 1,131 of Of those who claimed that the research  26,390 (4.0%) literature is important to them, 71% described their access as "fairly easy" or "very easy." 60% reported that access is easier now than 5 years ago; 20% said it is worse. Harley et al., NA Academics belong to a highly 2010  conservative system structured by disciplinary norms and organized around external peer review and assessment. There is little room for experimentation with new forms of publication, especially for new academics. Schonfeld 3,025 of Absence of fees is a top concern of and 35,184 (8.6%) authors selecting a journal in which Housewright, to publish. Free online access ranks 2010  lowest in the list of priorities. Disciplinary norms dominate attitudes and behavior. Ware, 2010 3,823 of 93% reported having "very easy" or  51,000 (7.5%) "fairly easy" access to research articles in journals. Reported by region (97% North America, 94% Western Europe, 91% Asia Pacific, 88% Latin America, 85% Middle East, 84% Eastern Europe, 78% Africa). Table 2 Key papers on the citation impact of free access to the scientific literature Authors Study design Study description Key findings Lawrence, Retrospective, 111,924 conference Overall citation 2001  observational papers in computer increase science, published (mean=336%, from 1989 to 2000. median=158%). Compared articles Greater citation freely available effect reported on the Internet for top 20 venues with print-only (mean=286%, articles. Included median=284%). controls for venue. Online availability and citation data from ResearchIndex. Antelman, Retrospective, 2,017 articles Mean OA citation 2004  observational (802 open access differences of [OA]) published in 45%-91%, depending high-impact on discipline. journals in Citation philosophy, differential is political science, greatest for engineering, and highly cited mathematics from articles. 1999 to 2002. OA defined as any version freely available on the web. Compared mean citations across disciplines without controls. Citation data from ISI. Harnad and Retrospective, 14 million Reports citation Brody, 2004 observational articles published ratios between 2.5  in physics between and 5.8 in favor 1991 and 2001. OA of OA. defined as any version of the article freely available on the web. Citation counts from ISI. Comparison methods not specified. Schwarz and Retrospective, 1,679 papers Papers posted to Kennicutt, observational published in astro-ph were 2004  Astrophysics cited more than Journal in 1999 twice as often. and 2002. 484 Describes (61%, 1999) and demographic 608 (72%, 2002) differences appeared in the between those who astro-ph section post to the arXiv of the arXiv. and those who do Citation data from not. ISI. Hajjem et Retrospective, 1.3 million Mean OA citation al., 2005 observational articles in 10 differences of  disciplines over 36%-172%, 12 years. depending on Automated discipline. detection of OA Citation status. Basic differential is citation greatest for comparison without highly cited controls. articles. Kurtz et Retrospective, Articles published Strong evidence al., 2005 observational in 7 core that citation  astrophysics effect is caused journals. OA by self-selection defined as any and early view version found in effects. No the arXiv. Various evidence of a analytical citation effect techniques. attributable to OA Citation data from status. the ADS system. Metcalfe, Retrospective, 7,089 articles Reports citation 2005  observational (4,156 OA) ratios between 1.6 published in 13 and 3.5 in favor journals. OA of OA, as high as defined as any 5.0 for articles version of the appearing in article found in Science and the astro-ph Nature. section of the arXiv. Basic comparison without controls. Citation data from ISI. Eysenbach, Prospective, 1,492 articles OA articles are 2006  observational (212 OA) published more likely to be in PNAS in 2004. cited than Author-pays OA subscription- articles were access articles 0- freely available 6 months, 4-10 from the journal months, and 10-16 website for the months after first 6 months; publication. (Odds then all articles ratios: 1.7, 2.1, were freely and 2.9, available. respectively.) Controls for article and author characteristics in a logistic regression model. Citation data from ISI. Henneken et Retrospective, Articles published Results support al., 2006 observational in 4 astronomy and Kurtz et al.,  physics journals. 2005. Self- Citations tracked selection and over 20 years, early-view effects before and after are responsible implementation of for the citation the arXiv. advantage of OA articles. Metcalfe, Retrospective, 170 articles Archived papers 2006  observational published in Solar received 2.6 and Physics and posted 1.6 times the as preprints in number of arXiv or in the citations as Montana State unposted papers University (MSU) for the arXiv and archive. Simple MSU, respectively. comparison of Awareness cited as citations at 3 probable cause. years. Davis and Retrospective, 2,765 articles OA articles Fromerth, observational (511 OA) published received 35% more 2007  in 4 math journals citations, on from 1997-2005. OA average. Citation defined as any differential is version found in greatest for the arXiv. Various highly cited analytical articles. Self- techniques with selection, not OA, controls. Citation is the probable data from cause. MathSciNet. Moed, 2007 Retrospective, 18,757 articles No evidence of a  observational (1,913 OA) citation advantage published in 6 as a result of OA. physics journals Strong evidence from 1992-2005. OA that a quality defined as any differential version of the between arXiv- article found in deposited and non- the Condensed deposited articles Matter section of is responsible for the arXiv. Various the citation analytical effect. Evidence techniques. for an earlier Citation data from citation lifecycle ISI. for deposited articles. Davis et Randomized 1,619 articles OA articles are al., 2008 controlled (247 OA) published more often  trial 2007 in 11 downloaded but are physiology no more likely to journals. Free be cited within access to articles the first year from the journal after publication. website. Controls for self-archiving. Logistic and negative-binomial regression analysis. Citation data from ISI. Gaule and Retrospective, 4,388 articles Citation effect Maystre, observational (17% OA) published becomes non- 2008  in PNAS from 2004- significant when a 2006. Author-pays full set of OA articles were controls is freely available included in the from the journal model. Citation website for the advantage cannot first 6 months; be attributed to then all articles OA. were freely available. Linear regression model includes covariates in addition to those used by Eysenbach (2006). Norris et Retrospective, 4,633 articles Average citation al., 2008 observational (2,280 OA) in advantage ranges  ecology, applied from 44%-88%, math, sociology, depending on and economics. OA field. defined as any freely available version of the article on the web. Simple comparisons without controls. Citation data from ISI. Davis, 2009 Retrospective, 11,013 articles Adjusted citation  observational (1,613 OA) advantage of 17% published in 11 for author-pays OA hybrid biomedical articles. Evidence journals from that citation 2003-2007. effect has Author-pays OA declined over articles were time, from 32% in freely available 2004 to 11% in from the journal 2007 website, with all journals offering delayed free access. Linear regression models with controls for article characteristics. Citation data from ISI. Evans and Retrospective, 26 million Publisher- Reimer, 2009 observational articles published mediated free  in 8,000 journals access increases from 1998-2005. citation rates by Measured effect of 8%, more for publisher-mediated poorer countries. free access with Effect of commercial online commercial online availability in access is greater Poisson regression than the effect of model, controlling free access. for journal volume effects. Citation data from ISI. Frandsen, Retrospective, 150 journals in Authors in 2009  observational biology (34 OA). developing Measured share of countries are not articles published especially likely by authors in to cite or publish developing in OA journals. countries and Some evidence that share of citations OA journals tend to OA journals. to cite OA Linear regression. journals more Citation data from frequently. ISI. Gaule, 2009 Retrospective, 43,150 articles in Indian reference  observational science and lists are 6% engineering shorter and cite published in 2007 more OA journals by authors in than Swiss Switzerland and reference lists. India. Linear Differences in regression with reference lists controls for are more journal effects. pronounced in biology and medicine than in physics, engineering, and chemistry. Lansingh and Retrospective, 895 articles Access status is Carter, 2009 case-control published in 6 not a significant  study ophthalmology predictor of journals (3 OA and citations when 3 subscription, article paired by impact characteristics factor) in 2003. are included in Multiple linear the regression regression with model. controls for article characteristics. Citation data from Scopus and Google Scholar. Calver and Retrospective, 1,151 articles and No citation Bradley, observational book chapters benefit for OA 2010  published in 8 articles when conservation article and biology journals authors in 2000. Citations characteristics gathered in 2008. are included in Linear regression the regression with controls for model. OA book article and author chapters were more characteristics. likely to be Citation data from cited. No citation Scopus. preference for authors in developing countries. Davis, 2010 Randomized 3,245 articles OA articles  controlled (712 OA) published received trial in 2007 and 2008 significantly more in 36 journals by downloads by more 7 publishers unique visitors covering sciences, yet were cited social sciences, neither more and humanities. frequently nor Free access to earlier than articles from the subscription- journal website. access control Controls for articles. self-archiving. Logistic and linear regression analysis. Citation data from ISI. Gargouri et Case-control, 27,197 articles Significant al., 2010 observational (6,215 OA) citation increase  published from for self-archived 2002-2006 by articles. Unable authors at 4 to distinguish institutions. institutional Ratio analysis and effect from logistic archiving effect. regression with controls. Citation data from ISI. Gentil- Retrospective, Articles and Group (2) articles Beccot et observational preprints in show 5-fold al., 2010 high-energy citation effect  physics published over the other 2 from 1991-2007. groups. 20% of Citation citations occur comparison between before formal 3 groups: (1) publication. posted to arXiv Unable to but not published, distinguish (2) posted to article effect arXiv and from archiving published, and (3) effect. published but not submitted to arXiv. Davis, 2011 Randomized Same dataset as OA articles  controlled Davis et al., received 119% more trial 2008. full-text downloads and 61% more PDF downloads from 32% more unique visitors in the first year. OA articles were cited no more frequently within the first 3 years. McCabe and Retrospective, 260,000 articles The large, Snyder, 2011 observational published in 100 positive citation  business and effects reported economics journals in prior from 1980-2005. observational Panel analysis, studies are likely controlling for to be artifacts of volume and time uncontrolled effects. Citation quality effects. data from ISI. Reports modest platform effects for journals hosted on JSTOR.
|Printer friendly Cite/link Email Feedback|
|Author:||Davis, Philip M.; Walters, William H.|
|Publication:||Journal of the Medical Library Association|
|Date:||Jul 1, 2011|
|Previous Article:||Mapping the core journals of the physical therapy literature.|
|Next Article:||Clinical and academic use of electronic and print books: the Health Sciences Library System e-book study at the University of Pittsburgh.|