Clarity and rigor in scientific writing.

"If you are out to describe the truth, leave elegance to the tailor," advised Einstein. It should go without saying that, in presenting scientific information, literary "elegance" or attention-drawing prose is out of place and counter-productive. The central requirements are clarity and rigor. Clear and rigorous scientific writing is dependent upon a use of language that favors simplicity and precision. In particular, giving insufficient attention to stylistic and linguistic precision will make scientific writing weaker and less readable. Let me offer some specific illustrations in three areas: denotation versus connotation, passive versus active wording, and present versus past tense. (Some of my examples are gratefully borrowed from biologist Antoinette M. Wilkinson's 1991 The Scientist's Handbook for Writing Papers and Dissertations.)Denotation versus connotationIdeally, a scientific term will have only one meaning. This will limit scientific writing to denotative rather than connotative or figurative language. A major transgression of this stricture is using words anthropomorphically, i.e, ascribing human attributes to nonhuman entities. You can avoid anthropomorphic language by providing an agent or focussing on the substance of the research. This sentence is anthropomorphic: "Lead contamination research has largely ignored the different cellular effects of lead absorption and has usually been content to accept them myopically as blockers of oxidative phosphorylation."Consider instead this revision: "The different cellular effects that lead absorption causes have largely been ignored in lead contamination research, and investigators have been content to accept..." The more serious anthropomorphic statements are those which are teleological, i.e., giving nonhuman entities intention toward a goal or objective, as in this sentence: "The farms in the sample packed their silage differently."Another practice which is not consonant with denotative language is the wording which draws attention to the writer or his/her writing. Examples include pretentious or pompous language (e.g., "aforementioned," "commence," "thereof") and the use of humor to "lighten" the formality of scientific writing. To an interested reader, humor is unnecessary, intrusive, and certainly out of character with the declarative and documentary nature of scientific writing. Also, given the topical and cultural nature of humor, readers who are not "insiders" may find it confusing.Passive versus active wordingA second factor that has an influence on clarity and rigor in scientific writing is the use of passive versus active constructions. Scientists use passive wording regularly in their writing. Critics of passive constructions point out that passives are weak, that they give a specious objectivity to research, and that, in not providing an agent, they allow the researcher to avoid accountability. These criticisms do have some merit, although use of passives does not always present such problems. In fact, sometimes passives are actually unavoidable ("Aluminum is readily oxidized") or even useful--e.g., for emphasis. The following passive sentence, for instance, emphasizes tubercle formation: "The formation of tubercles was stimulated by the removal of the apical meristem." Notice how a revision that changes the passive to an active construction also shifts the emphasis to apical meristem: "The removal of the apical meristem stimulated the formation of tubercles."Many passive constructions are unnecessary and weak. "The pathogen is most commonly parasitic on clovers, but alfalfa can also be severely damaged" should be revised to "...but can also severely damage alfalfa." And, "The size had to be small enough that the implant could be easily adjusted to by the tissue" should be revised to "...that the tissue could easily adjust to the implant."Finally, it is not necessarily true that scientists use the passive voice to appear more objective or to avoid accountability. First, there may in fact be no person as agent. And even when there is a person as agent, the interest of readers of scientific papers is normally not focussed on the agent, but on the research. For instance, passive wording is common in procedural descriptions: "Cells were placed in a thin chamber... The coverslips were siliconized to... The chamber was placed on... A micropipette was connected to... Zero pressure was determined by..." Revising these passives to provide an agent makes the subject "I" ("I placed cells...," "I siliconized...," etc.) instead of cells, coverslips, chamber, micropipette, and pressure. This revision may make the description more direct, active, and stronger, and the scientist more accountable, but the subject has shifted from the objects to the author, who is of little interest relative to the procedure described. Moreover, the new subject "I" and its verb at the beginning of each sentence are barriers in front of the material of interest.Present versus past tenseA third element that affects a scientific text's clarity and rigor is tense. The tense of verbs is an important means of differentiating between reporting of experimental observations (performed in the past) and discussion (which includes present commentary). The writer should not generalize and report the findings from an experiment in the present tense, as though they were universal or general truths. Consider the following options:* "Jones and Smith (1989) found (vs. find) a sharp increase in prolactin at day 21."* "There is a sharp increase in prolactin at day 21."* "Prolactin increases sharply after treatment with..."In the first sentence, replacing the past tense by the present tense, "find," leads to an inaccurate statement, since Jones and Smith are not continuing their experiment and it is not certain that they would obtain the same result if they did. In the second sentence, the present tense changes the statement of a research finding into one of generally accepted knowledge. The third statement would be a very broad generalization, without adequate scientific support.A writer may try to use the present tense to express a prior finding in a way that indicates its continued "truth" in the present: "It was found that the level of acetaldehyde in the blood increases with chronic alcohol consumption." But such results might not be the case in future studies. Thus, reporting these results entirely in the past tense would not only be more accurate, but would also ensure that this statement would remain accurate in the future, even with different findings. The other option, i.e., writing the statement entirely in the present tense -- "Chronic alcohol consumption increases blood acetaldehyde levels" -- generalizes and so is not accurate.The same decisions about tense must be made in a report's conclusion. While the present tense lends itself to general discussion, tense in concluding statements based on the findings must be carefully considered. For instance, the statement "It is concluded that carbohydrate loading affected (vs. affects) endurance" maintains the conclusion as a past inference of the past results; using the present tense, "affects," would create a general statement regarding the results, which is scientifically less accurate. Conclusions about the research may be in the present tense, but those that generalize a finding should be kept in the past tense: "The close correspondence between the chemical uptake by plants and the RWD indicates (indicated) that the rate of root growth was more important than the specific absorption rate." Generally speaking, statements in the past tense are more rigorous scientifically. The regular use of present tense is of course appropriate in discussions and in developments that include equations.Among the most important elements that affect clarity and rigor in scientific writing are the decisions an author makes regarding denotative/connotative language, active/passive constructions, and tense. Upon deeper consideration of the cliche that "the facts speak for themselves," the meticulous scientific writer will realize that interposed between the data and their accurate communication is a human being who must do everything possible to ensure that readers are able to understand and utilize the information transmitted.Robert Goldbort, Ph.D., Assistant Professor, Department of English, Indiana State University, Terre Haute, IN 47809.