An objective of organizing a research paper is to allow people to read your work selectively. When I research a topic, I may be interested in just the methods, a specific result, the interpretation, or perhaps I just want to see a summary of the paper to determine if it is relevant to my study.
For most studies, a proper research report includes the following sections, submitted in the order listed, each section to start on a new page. Some journals request a summary to be placed at the end of the discussion. Some techniques articles include an appendix with equations, formulas, calculations, etc. Some journals deviate from the format, such as by combining results and discussion, or combining everything but the title, abstract, and literature as is done in the journal Science. Your reports will adhere to the standard format.
For detailed guidelines with examples, consult a text that is dedicated to scientific communication, such as McMillan, VE. "Writing Papers in the Biological Sciences (2nd edition)." Boston: Bedford Books, 1994.
Common errors in student research reports have been collected and summarized, to help you avoid a number of pitfalls. You may also want to keep in mind how lab reports are usually graded as you prepare your work.
In all sections of your paper, use paragraphs to separate each important point (except for the abstract), and present your points in logical order. Use present tense to report background that is already established. For example, 'the grass is green.' Always use past tense to describe results of a specific experiment, especially your own. For example, 'When weed killer was applied, the grass was brown.' Remember - present tense for background, and past tense for results.
Select an informative title, such as "Role of temperature in determination of the rate of development of Xenopus larvae." A title such as "Biology lab #1" is not informative. Include the name(s) and address(es) of all authors, and date submitted.
Summarize the study, focusing on the results and major conclusions, including relevant quantitative data. It must be a single paragraph, and concise. It should stand on its own, therefore do not refer to any other part of the report, such as a figure or table. Avoid long sections of introductory or explanatory material. As a summary of work done, it is written in past tense.
Introduce the rationale behind the study, including
Include appropriate background information (but please do not write everything you know about the subject).
The purpose of this section is to document all of your procedures so that another scientist could reproduce all or part of your work. It is not designed to be a set of instructions. As awkward as it may seem, it is standard practice to report methods and materials in past tense, third person passive. Your laboratory notebook should contain all of the details of everything you do in lab, plus any additional information needed in order to complete this section.
While it is tempting to report methods in chronological order in a narrative form, it is usually more effective to present them under headings devoted to specific procedures or groups of procedures. Some examples of separate headings are "sources of materials," "assay procedures,"cell fractionation protocol," and "statistical methods." Try to be succinct without sacrificing essential information. Omit any background information or comments. If you must explain why a particular procedure was chosen, do so in the discussion.
Omit information that is irrelevant to a third party. For example, no third
party cares what color ice bucket you used, or which individual logged in the
data. You need not report sources of basic chemicals that would be found in
any supply cabinet, such as sodium chloride or potassium phosphate. Report how
procedures were done, not how they were specifically performed on a particular
day. For example, report "samples were diluted to a final concentration
of 2 mg/ml protein;" don't report that '135 microliters of sample one was
diluted with 330 microliters of buffer to make the proteins concentration 2
Raw data are never included in a research paper. Analyze your data, then present the analyzed (converted) data in the form of a figure (graph), table, or in narrative form. Present the same data only once, in the most effective manner. By presenting converted data, you make your point succinctly and clearly.
Figures are preferable to tables, and tables are preferable to straight text. However, many times a figure is inappropriate, or the data come across more clearly if described in narrative form.
To give your results continuity, describe the relationship of each section of converted data to the overall study. For example, rather than just putting a table in the paper and going on to the discussion, write, 'In order to test the null hypothesis that dust particles are responsible for the blue color of the sky, we observed the results of filtering air through materials of decreasing pore size. Table 1 lists the spectrum of transmitted light at right angles to the light path through air filtered through different pore sizes.' Then present your table, complete with title and headings.
All converted data go into the body of the report, after the methods and before the discussion. Do not stick graphs or other data onto the back of the report just because you printed or prepared them separately.
Do not draw conclusions in the results section. Reserve data interpretation for the discussion.
Interpret your data in the discussion. Decide if each hypothesis is supported, rejected, or if you cannot make a decision with confidence. Do not simply dismiss a study or part of a study as "inconclusive." Make what conclusions you can, then suggest how the experiment must be modified in order to properly test the hypothesis(es).
Explain all of your observations as much as possible, focusing on mechanisms. When you refer to information, distinguish data generated by your own studies from published information or from information obtained from other students. Refer to work done by specific individuals (including yourself) in past tense. Refer to generally accepted facts and principles in present tense. For example, "Doofus, in a 1989 survey, found that anemia in basset hounds was correlated with advanced age. Anemia is a condition in which there is insufficient hemoglobin in the blood."
Decide if the experimental design adequately addressed the hypothesis, and whether or not it was properly controlled. One experiment will not answer an overall question, so keeping the big picture in mind, where do you go next? The best studies open up new avenues of research. What questions remain? Did the study lead you to any new questions? Try to think up a new hypothesis and briefly suggest new experiments to further address the main question. Be creative, and don't be afraid to speculate.
List all literature cited in your report, in alphabetical order, by first author. In a proper research paper, only primary literature is used (original research articles authored by the original investigators). Some of your reports may not require references, and if that is the case simply state "no references were consulted."
Through measurement of steady state transmembrane potentials (Em) using an intracellular microelectrode recording system, we studied the possible direct role of the sodium/potassium pump in maintenance of Em in crayfish extensor muscles. We varied extracellular sodium ([Na+]out) and potassium ion ([K+]out) concentrations in order to test the predictability of the equilibrium potential model (using the Nernst equation for potassium) and the diffusion potential model as described by the Goldman/Hodgkin/Katz equation. Combined Em measurements from four preparations before and after treatment with 6 mM ouabain showed no significant difference (-59.2 +/- 5.8 before treatment, -56.8 +/- 5/3 after treatment, p=0.06). The Nernst equation for potassium failed to predict Em at low [K+]out but was adequate when [K+]out was elevated to five times control values (+100% error at 0.3 x [K+]out, +22% error at 5 x [K+]out). The Goldman equation was off by +20% and +2.5% respectively, for the same conditions. At [Na+]out of 1x, 0.5x, 0.2x, and 0.05x normal the Goldman equation prediction was off -2%, +4%, +11%, and +7%, respectively. Since measured Em was consistently lower than predicted Em part of the error may be due to a slight electrogenic contribution by the pump. Although the diffusion potential model is a better predictor of Em than the equilibrium potential model pump activity is not sufficient to account for all of the deviation of predicted from measured values.
Prior to the development of modern techniques for measurement of transmembrane potentials and accurate quantitation of ion conductances, a model describing the cell membrane as a potassium electrode appeared suitable for prediction of the steady state transmembrane potential under physiological conditions. This equilibrium potential model, developed by J. Bernstein, used the Nernst equation for potassium to predict the transmembrane potential. Failure of this model to predict the positive overshoot or hyperpolarization phases of action potentials led to refinement of the model, in which the transmembrane potential is viewed as a diffusion potential. In the second model the contribution of an ion depends on membrane permeability to that ion, as well as its concentration on both sides of the membrane.
In testing the predictive value of each model for transmembrane potentials of crayfish extensor muscle, one question concerns the direct "electrogenic" contribution of the pump. To what extent is the pump necessary for moment-to-moment maintenance of the membrane potential? How might the direct contribution of the pump affect predictability of either model? To test the suitability of both models in predicting the transmembrane potential for this type of tissue we evaluated the role of the pump by measurement of transmembrane potentials before and after poisoning the preparations with ouabain (a direct inhibitor of the sodium-potassium pump). To further test the predictability of each model we varied extracellular potassium and sodium ion concentrations, measured the response of the steady state transmembrane potentials, and compared them with values predicted by the Nernst and Goldman equations, respectively. The results should help determine if the diffusion potential model must be modified to a more universal form in order to predict membrane potentials from a wide range of tissues from different species.
and Intended Use
Created by David R. Caprette (firstname.lastname@example.org), Rice University 25 Aug 1995
Updated 16 May 2000