Criteria for Success

A successful Methods section contains the following elements:

  1. The rationale for selecting your methodology and constructing your apparatus. What are the advantages and limitations? What are the constraints? How does your methodology help you determine what you want to know?
  2. Sufficient information about the setup to enable a reader to replicate your findings. What materials or techniques did you use? What did you build versus what was purchased off-the-shelf? Characterize the relevant performance specifications of your components.

Purpose

A Methods section describes how you will approach the questions and knowledge gap posed in the Introduction. Not all readers will be interested in this information. For those who are, the Methods section has two purposes:

  1. Allow readers to judge whether the results and conclusions of the study are valid.

The interpretation of your results depends on the methods you used to obtain them. A reader who is skeptical of your results will read your Methods section to see if they can be trusted. They’ll want to know that you chose the most appropriate apparatus, that your assumptions were reasonable, and that you performed the necessary controls. Without this content, skeptical readers may think your data, and therefore any conclusions drawn from it, are unreliable.

  1. Allow readers to repeat the study.

For readers interested in replicating your study, the Methods section should provide enough information for them to obtain the same or similar results. This applies equally for the skeptical reader as for one who needs similar or extended data.

Analyze your audience

Typically, only readers in your field will want to replicate your study or have the knowledge to assess your methodology. More general audiences will read the Introduction and then proceed straight to the Results. You can therefore typically assume that people reading your Methods understand methodologies that are frequently used in your field. To gauge the level of detail necessary for a given method, you can look at articles previously published in your target journal.

If your paper is designed to appeal to experts in more than one field, you still need to write your Methods for a targeted set of experts. For example, say you implemented a novel numerical technique to study the behavior of bouncing fluid droplets. Is your goal to show fluid dynamicists additional insights from the numerical techniques, or engage applied mathematicians to improve the numerical model’s performance? In the former case, assume less computational expertise. In the latter, assume less fluids experience, i.e., explain what assumptions the current model makes.

Skills

State the reasons for choosing your methodology

A reader looking to assess your methodology will read your Methods section to judge your experimental design. When describing your approach, place more emphasis on how and why you applied a method rather than on how you performed the method. For example, you don’t need to explain how to build an instrumentation amplifier, but you might want to describe why a linear Lorentz-force actuator is more appropriate than a solenoid or ball screw linear actuator for your apparatus (and, potentially, why you didn’t use another method).

Specify the purpose of the method “To generate an input motion to the system, we used a linear Lorentz-force actuator.”
Explain why you used the particular method “Complete measurements require multiple excitation waveforms over a large frequency bandwidth spanning 0.1 to 100 Hz.”
Justify why you didn’t use another method “While a solenoid has the bandwidth, it lacks waveform control; conversely, while a ball-screw linear actuator has straightforward waveform control, it is comparatively low-frequency.”

Use subheadings to organize content

As recommended for your Results section, use subheadings within your Methods to group related experiments and establish a logical flow. Write your Results section first, and then follow the order of Results subheadings when writing your Methods. The parallel structure will make it easy for readers to locate corresponding information in the two sections.

Subheadings for Methods and Results may not exactly correspond. Sometimes you may need multiple Methods subheadings to explain one Results subheading. Other times one Method subheading is enough to explain multiple Result subheadings.

Note: For some journals, especially for letter-style submissions, subheadings are not allowed or recommended by the editors. Check the journal style guidelines before committing to subheadings.

Provide minimal essential detail

For readers to replicate your study, you must provide enough detail to allow them to reach the same conclusions as you do in your paper. Include only those details—anything more is extraneous. Specify any factor that might change the conclusions in your paper. State the accuracy limits of the instrumentation you used and any uncertainties in material properties.

You can cite papers for standard methods, but any modifications or alterations should be clearly stated. When citing methods, cite the original paper in which a method was described instead of a paper that used the method. This helps avoid chains of citations that your reader must follow to find information about the method.

Depending on the journal, field, and novelty of the techniques, it is sometimes most appropriate to describe minimal detail in the article body, and then to include a more detailed appendix or supplemental section that describes the methodology in enough detail to be reproduced exactly.

Resources and Annotated Examples

Annotated Example 1
Annotated Example 1

This is the methods section of a fluid mechanics paper published in Nature Physics. 417 KB

Annotated Example 2
Annotated Example 2

This is the methods section of a fluid mechanics paper published in the Journal of Fluid Mechanics. 88 KB