Scientific papers are for sharing your own original research work with other scientists or for reviewing the research conducted by others. As such, they are critical to the evolution of modern science, in which the work of one scientist builds upon that of others. To reach their goal, papers must aim to inform, not impress. They must be highly readable — that is, clear, accurate, and concise. They are more likely to be cited by other scientists if they are helpful rather than cryptic or self-centered.
Scientific papers typically have two audiences: first, the referees, who help the journal editor decide whether a paper is suitable for publication; and second, the journal readers themselves, who may be more or less knowledgeable about the topic addressed in the paper. To be accepted by referees and cited by readers, papers must do more than simply present a chronological account of the research work. Rather, they must convince their audience that the research presented is important, valid, and relevant to other scientists in the same field. To this end, they must emphasize both the motivation for the work and the outcome of it, and they must include just enough evidence to establish the validity of this outcome.
Papers that report experimental work are often structured chronologically in five sections: first, Introduction; then Materials and Methods, Results, and Discussion (together, these three sections make up the paper's body); and finally, Conclusion.
- The Introduction section clarifies the motivation for the work presented and prepares readers for the structure of the paper.
- The Materials and Methods section provides sufficient detail for other scientists to reproduce the experiments presented in the paper. In some journals, this information is placed in an appendix, because it is not what most readers want to know first.
- The Results and Discussion sections present and discuss the research results, respectively. They are often usefully combined into one section, however, because readers can seldom make sense of results alone without accompanying interpretation — they need to be told what the results mean.
- The Conclusion section presents the outcome of the work by interpreting the findings at a higher level of abstraction than the Discussion and by relating these findings to the motivation stated in the Introduction.
(Papers reporting something other than experiments, such as a new method or technology, typically have different sections in their body, but they include the same Introduction and Conclusion sections as described above.)
Although the above structure reflects the progression of most research projects, effective papers typically break the chronology in at least three ways to present their content in the order in which the audience will most likely want to read it. First and foremost, they summarize the motivation for, and the outcome of, the work in an abstract, located before the Introduction. In a sense, they reveal the beginning and end of the story — briefly — before providing the full story. Second, they move the more detailed, less important parts of the body to the end of the paper in one or more appendices so that these parts do not stand in the readers' way. Finally, they structure the content in the body in theorem-proof fashion, stating first what readers must remember (for example, as the first sentence of a paragraph) and then presenting evidence to support this statement.
The section headings (Abstract, Introduction, etc.) should be centered and the body of each section should follow immediately below the heading. Do not begin each section on a new page. If one section ends part of the way down the page, the next section heading follows immediately on the same page.
One important general rule to keep in mind is that a scientific paper is a report about something that has been done in the past. Most of the paper should be written in the PAST TENSE (was, were). The present tense (is, are) is used when stating generalizations or conclusions. The present tense is most often used in the Introduction, Discussion and Conclusion sections of papers. The paper should read as a narrative in which the author describes what was done and what results were obtained from that work.
Every scientific paper must have a self-explanatory title. By reading the title, the work being reported should be clear to the reader without having to read the paper itself. The title, "A Biology Lab Report", tells the reader nothing. An example of a good, self-explanatory title would be: "The Effects of Light and Temperature on the Growth of Populations of the Bacterium, Escherichia coli ". This title reports exactly what the researcher has done by stating three things:
If the title had been only "Effects of Light and Temperature on Escherichia coli ", the reader would have to guess which parameters were measured. (That is, were the effects on reproduction, survival, dry weight or something else?) If the title had been "Effect of Environmental Factors on Growth of Escherichia coli ", the reader would not know which environmental factors were manipulated. If the title had been "Effects of Light and Temperature on the Growth of an Organism", then the reader would not know which organism was studied. In any of the above cases, the reader would be forced to read more of the paper to understand what the researcher had done.
Exceptions do occur: If several factors were manipulated, all of them do not have to be listed. Instead, "Effects of Several Environmental Factors on Growth of Populations ofEscherichia coli " (if more than two or three factors were manipulated) would be appropriate. The same applies if more than two or three organisms were studied. For example, "Effects of Light and Temperature on the Growth of Four Species of Bacteria" would be correct. The researcher would then include the names of the bacteria in the Materials and Methods section of the paper.
The abstract section in a scientific paper is a concise digest of the content of the paper. An abstract is more than a summary. A summary is a brief restatement of preceding text that is intended to orient a reader who has studied the preceding text. An abstract is intended to be self-explanatory without reference to the paper, but is not a substitute for the paper.
The abstract should present, in about 250 words, the purpose of the paper, general materials and methods (including, if any, the scientific and common names of organisms), summarized results, and the major conclusions. Do not include any information that is not contained in the body of the paper. Exclude detailed descriptions of organisms, materials and methods. Tables or figures, references to tables or figures, or references to literature cited usually are not included in this section. The abstract is usually written last. An easy way to write the abstract is to extract the most important points from each section of the paper and then use those points to construct a brief description of your study.
The Introduction is the statement of the problem that you investigated. It should give readers enough information to appreciate your specific objectives within a larger theoretical framework. After placing your work in a broader context, you should state the specific question(s) to be answered. This section may also include background information about the problem such as a summary of any research that has been done on the problem in the past and how the present experiment will help to clarify or expand the knowledge in this general area. All background information gathered from other sources must, of course, be appropriately cited. (Proper citation of references will be described later.)
A helpful strategy in this section is to go from the general, theoretical framework to your specific question. However, do not make the Introduction too broad. Remember that you are writing for classmates who have knowledge similar to yours. Present only the most relevant ideas and get quickly to the point of the paper. For examples, see the Appendix.
MATERIALS AND METHODS
This section explains how and, where relevant, when the experiment was done. The researcher describes the experimental design, the apparatus, methods of gathering data and type of control. If any work was done in a natural habitat, the worker describes the study area, states its location and explains when the work was done. If specimens were collected for study, where and when that material was collected are stated. The general rule to remember is that the Materials and Methods section should be detailed and clear enough so that any reader knowledgeable in basic scientific techniques could duplicate the study if she/he wished to do so. For examples, see the Appendix.
DO NOT write this section as though it were directions in a laboratory exercise book. Instead of writing:
Simply describe how the experiment was done:
Also, DO NOT LIST the equipment used in the experiment. The materials that were used in the research are simply mentioned in the narrative as the experimental procedure is described in detail. If well-known methods were used without changes, simply name the methods (e.g., standard microscopic techniques; standard spectrophotometric techniques). If modified standard techniques were used, describe the changes.
Here the researcher presents summarized data for inspection using narrative text and, where appropriate, tables and figures to display summarized data. Only the results are presented. No interpretation of the data or conclusions about what the data might mean are given in this section. Data assembled in tables and/or figures should supplement the text and present the data in an easily understandable form. Do not present raw data! If tables and/or figures are used, they must be accompanied by narrative text. Do not repeat extensively in the text the data you have presented in tables and figures. But, do not restrict yourself to passing comments either. (For example, only stating that "Results are shown in Table 1." is not appropriate.) The text describes the data presented in the tables and figures and calls attention to the important data that the researcher will discuss in the Discussion section and will use to support Conclusions. (Rules to follow when constructing and presenting figures and tables are presented in a later section of this guide.)
Here, the researcher interprets the data in terms of any patterns that were observed, any relationships among experimental variables that are important and any correlations between variables that are discernible. The author should include any explanations of how the results differed from those hypothesized, or how the results were either different from or similar to those of any related experiments performed by other researchers. Remember that experiments do not always need to show major differences or trends to be important. "Negative" results also need to be explained and may represent something important--perhaps a new or changed focus for your research.
A useful strategy in discussing your experiment is to relate your specific results back to the broad theoretical context presented in the Introduction. Since your Introduction went from the general to a specific question, going from the specific back to the general will help to tie your ideas and arguments together.
This section simply states what the researcher thinks the data mean, and, as such, should relate directly back to the problem/question stated in the introduction. This section should not offer any reasons for those particular conclusions--these should have been presented in the Discussion section. By looking at only the Introduction and Conclusions sections, a reader should have a good idea of what the researcher has investigated and discovered even though the specific details of how the work was done would not be known.
In this section you should give credit to people who have helped you with the research or with writing the paper. If your work has been supported by a grant, you would also give credit for that in this section.
This section lists, in alphabetical order by author, all published information that was referred to anywhere in the text of the paper. It provides the readers with the information needed should they want to refer to the original literature on the general problem. Note that the Literature Cited section includes only those references that were actually mentioned (cited) in the paper. Any other information that the researcher may have read about the problem but did not mention in the paper is not included in this section. This is why the section is called "Literature Cited" instead of "References" or "Bibliography".
The system of citing reference material in scientific journals varies with the particular journal. The method that you will follow is the "author-date" system. Listed below are several examples of how citations should be presented in the text of your paper. The name(s) of the author(s) and year of publication are included in the body of the text. Sentence structure determines the placement of the parentheses.