by Dr. Brewer, ScienceDocs Editor and Writer
“I keep six honest serving-men:
(They taught me all I knew)
Their names are What and Where and When
And How and Why and Who.”
– Rudyard Kipling “The Elephant’s Child”
Scientists try to understand the world empirically. Through observation and experiment, we seek to build reliable knowledge.
In our scientific articles and other reports, we describe what we did and what we found. Usually in our reports we also discuss hypotheses, theories, interpretations of results, implications, and/or speculation. But these are all secondary matters. The most important parts of any scientific report are the methods and results sections because they contain the evidence.
The information in the methods section (or “materials and methods” or “method” section) allows readers to make sense of and evaluate the results. A results section without a preceding methods section is like a punch line for a joke without the setup. (Unfortunately, some journals now put the methods section at the end of an article, in small print, or remove it from the main article entirely, which undermines scientific understanding and de-emphasizes the heart of research.)
The methods section should also include a full enough description of study procedures to enable other researchers to replicate the research. This is crucial. Why should anyone care about a study that can’t be repeated?
Specifically, in the methods section, we answer the 5 Ws and one H. These are the questions that Kipling wisely recognized as the keys to knowledge: who, what, where, when, why, and how.
The methods section is the easiest part of a scientific report to write. We already know what we did, and no interpretation is required. Still, sometimes authors leave out essential information. By checking whether our methods sections address the fundamental questions, we can reduce the chance of omitting something important.
Who? Although descriptions of research participants – human or animal subjects – are standard, many authors write methods sections, often in passive voice, as if no researchers were involved in the study (e.g., “specimens were collected”, “surveys were administered”). It can be useful to identify who carried out particular tasks in a study. Also, it is critical to note when the sample of participants is the same as or overlaps with a sample from another report (or study). More generally, if the study is the same as that in another report (but focused perhaps on a different outcome or topic), the other report(s) must be cited. Otherwise, readers may believe, incorrectly, that the separate reports represent different studies.
What? The methods section focuses on study procedures and the equipment, facilities, materials, and software used to carry them out. Despite this, authors sometimes neglect relevant details, such as the sources (including manufacturer and city) of the equipment, materials, or software. For the most important methodological aspects of a study, it is best to be very explicit. For instance, if a study involved randomization (e.g., random assignment or probability sampling), we should describe how we randomized (computerized random number generator, random number table, digits from atmospheric noise [www.random.org], etc.).
Where? For field studies of any kind or research involving people, it is essential to report the study location (at least country/region of country, and ideally city or town as well). In many cases, the specific geographic and/or social context should be described.
When? In methods sections, authors often omit the date of data collection or other key study activities. We can present a more complete picture by reporting at least the month(s) and year(s). Sometimes, specific days, days of the week, or even times of day may be relevant, depending on the topic.
Why? In the introduction section of a scientific report, we explain the reasons for conducting the research. With this background, it is usually clear why we used the methods we did. However, occasionally the rationale for one or another aspect of the methods may not be readily apparent. In this situation, we need to give the rationale in the methods section. For complicated studies with many components, we can briefly explain the purpose of each component before describing it.
How? It is worthwhile to consider whether we have documented the ways in which we implemented our methods. For example, routine yet critical aspects of studies should be described, such as mode of administration (for substances into bodies/organisms or surveys to respondents), consent procedures and other ethical matters, protocols for preventing sample contamination, incentives given to participants, and participant recruitment strategies, among other topics.
Checklists for crucial elements to include in a methods section may helpful to address many of these questions. The EQUATOR Network (http://www.equator-network.org/) gives many such checklists for research designs in the health and social sciences.
Because we report what we did in the methods section, we write the section in past tense. And because what we did is distinct from what we found, we do not include any results in the methods section. One exception to this rule is that, in some fields, researchers describe the measurement characteristics of instruments in the methods section, generally for substantively-, rather than methodologically-, oriented studies.
Although it’s important to report methods fully, we can also do so concisely. We can simply mention a method that is common in a field and give one or more citations to sources that describe it.
Nonetheless, sometimes the methods section is too long to be included in the main text of a scientific report. In this circumstance, we can create a “supplementary material” document to hold either a full description of the methods or just certain parts that we removed from the main text of the report. If the publisher of a report doesn’t include supplementary material online, then we can put it in an independent, long-term archive, such as the Internet Archive (http://www.archive.org) or the Open Science Framework (http://www.osf.io), and cite web address for the supplementary material in the main scientific report.
Journals and fields vary on the precise details to be included in a methods section and the format in which they should be presented. Those guidelines and my tips here can help make our research more understandable and reproducible.
Learn more about ScienceDocs Editor Dr. Bewer