The Methods and Materials section of a paper often seems the least interesting to read, or to write, but it serves several essential purposes. First, it demonstrates to readers that the research was designed appropriately and conducted competently. Scientists are skeptical readers. They won’t have any confidence in your results unless the Methods section convinces them those results come from the correct experiment, carried out correctly. Second, this section allows other researchers to repeat the research for themselves. The ability to replicate a study and get the same results is a central part of science. If possible, your materials and methods section should be written in enough detail to allow another researcher to repeat what you did. (As science develops ever more complex techniques for probing nature this becomes increasingly difficult to achieve.) Where established protocols or techniques are used, it is often acceptable to simply cite a previously published work which sets out the procedure in detail. However, the procedures should always be described in sufficient detail that readers have a clear sense of the basic approach being taken.
What to include:
One of the trickiest parts of writing the Methods section is determining the correct level of detail. Always ask yourself: Does the reader need to know this to understand and repeat the experiment? (Pechenik 1996) Let’s say you performed an experiment to test the effects of vitamin E by injecting lab rats with different doses. It would be essential for the reader to know the number of rats injected, and the dosages used, but it would probably not be necessary to include the brand of syringe used, since any standard sterilized syringe should give equivalent results. If in doubt, include the information. Students tend to include too little detail in their Methods rather than too much.
Know your audience:
Part of the challenge of knowing what details to include is knowing what you can assume your audience already knows. You can always assume your audience has a basic understanding of biology, but how much detailed knowledge of your subject area you can expect will depend on the paper’s destination. You should never assume your reader has prior knowledge of your research. (Even an instructor who has coached you every step of the way as you prepared a paper will be reading and marking it from the perspective of someone seeing the research for the first time.)
No list of materials:
Always describe your materials in the context of how they were used. A list of materials is a waste of space and tells your reader little. Simply describe the methods used to collect your data, and note the materials used for each.
Use figures:
Pictures are often helpful in explaining methodology. These could include diagrams of apparatus, maps of the study area showing sampling locations, flowcharts for complicated protocols, etc. A picture really is often worth a thousand words. All graphics included in your paper should be numbered and captioned as figures.
Interpret when necessary:
Methods should be concise and factual, but take the space to explain any choices which will not make sense to your readers. If one of your treatment groups was much smaller than the other because a badger ate several of the ground squirrels you were studying, point that out.
Stat tests are methods:
Statistical tests and other types of analysis performed on your data are part of your methods. Commonly used statistical tests need not be described, but if any explanation of your analysis is needed, the methods section is the appropriate place. If you used a test which is not widely known, a short description and a citation of the source is warranted.