When writing manuscripts for publication, there are many important details that need to be included to present a well balanced, comprehensive description of your work. One of the most important but often underrated of these details is the limitations section of your manuscript. Many authors often experience difficulty writing about the limitations of their work or are reluctant to include them at all. However, to ensure that you provide accurate context for your work and give readers sufficient information to properly evaluate the relevance and impact of your results, they must be included. So what’s the best way to go about describing limitations without invalidating your findings? Let’s approach our strategy in a methodical way by first looking at the types of limitations you might encounter.
Types of Limitations
Before you even start your study, you may be aware that there are certain limitations to what you want to test or what possible results may come of your efforts. The procedures you have available or specific constraints on the study population may ultimately affect what outcomes you can obtain. These we can refer to as study design limitations.
Another type of limitation to consider is what we might call an impact limitation. Even if your study has strong design and excellent statistics, it can suffer from limited impact from factors such as a strong regional focus, being too population-specific, or the field being only conducive to incremental findings.
A final type of limitation is that of statistical or data limitations. Sometimes you may not be able to collect as much or as good data as you intended, or perhaps enrollment was more difficult than expected, underpowering your results. Statistical limitations can also stem from study design, producing more serious limitations in terms of interpreting the findings.
Although these three types of limitations are often connected, to help identify specific limitations that should be mentioned in your manuscript it helps to consider these three categories separately to ensure you don’t miss anything.
How to Describe Your Limitations
Now that you know how to identify possible limitations in your study, the question turns to how to go about describing them in your article. In our experience, we’ve found that many authors are reluctant to write about their limitations because they feel it weakens their study and is pointing out flaws others may not have noticed. While this can make a person feel vulnerable, everyone knows that limitations are a part of science, and are looking for them anyways, so it’s better to be upfront about them. You can counter the reader’s presumed negative interpretation by providing them with an explanation for each limitation, showing why the results are still important.
For example: Your study looked at the efficacy of a new diabetes treatment in Japanese patients. The results were very positive; however, because you only looked at Japanese patients, these findings may not translate to patients of other ethnicities. A statement to this effect could be declared in the limitations section of your manuscript, followed up by a comment about how the results might still be widely applicable as they will help with patient-specific treatment in all parts of the world.
If you have results that are particularly novel or you’re publishing in a little-researched field, another approach to supporting your findings in spite of limitations is to reinforce the novelty of your results. When breaking new ground, it is likely that there are still a lot of gaps in the knowledge base that need to be filled. Therefore, a good follow-up statement for this type of limitation is to describe what, based on these results, the next steps would be to build a stronger overall evidence base.
Now, it is possible that your study will have a fairly critical flaw (usually in the study design) that decreases confidence in your findings. In this case, it will probably also be apparent to others, so it’s best to explain why this error or flaw occurred. You can still explain why the study is worth repeating or how you plan to re-test the phenomenon, but it is also likely that your publication goals may need to be lowered if you still plan to publish your work.
Limit Your Expectations
No one expects science to be perfect the first time and while your peers can be highly critical, no one’s work is beyond limitations. Our knowledge base is built on uncovering each piece of the puzzle, one at a time, and limitations show us where new efforts need to be made. So much like peer review, don’t think of limitations as being inherently bad, but more an opportunity for a new challenge. In the end, your limitation may be someone else’s inspiration.
By Amanda Hindle, Senior Editor
We recommend you to have the technical content of your manuscript reviewed by an independant expert in your field BEFORE submitting to your target journal. This will allow you to improve the content based on advice and recommendations from an experienced expert and will minimize the need for revisions after submission.
The limitations and delimitations sections of your research proposal describe situations and circumstances that may affect or restrict your methods and analysis of research data.
Limitationsare influences that the researcher cannot control. They are the shortcomings, conditions or influences that cannot be controlled by the researcher that place restrictions on your methodology and conclusions. Any limitations that might influence the results should be mentioned.
When considering what limitations there might be in your investigation, be thorough. Consider all of the following:
- your analysis.
- the nature of self-reporting.
- the instruments you utilized.
- the sample.
- time constraints.
Inqualitative research certain limitations might mean that the findings cannot be generalized to the larger population. This is especially true when the definition of the population is broad (ex: elderly women)
Delimitationsare choices made by the researcher which should be mentioned. They describe the boundaries that you have set for the study. This is the place to explain:
- the things that you are not doing (and why you have chosen not to do them).
- the literature you will not review (and why not).
- the population you are not studying (and why not).
- the methodological procedures you will not use (and why you will not use them).
Limit your delimitations to the things that a reader might reasonably expect you to do but that you, for clearly explained reasons, have decided not to do.
Delimitations define the parameters of the investigation. In educational research the delimitations will frequently deal with such items as population/sample, treatment(s), setting, and instrumentation.
As you complete the limitations and delimitations sections on your planning guide, you may want to go back to the Sample Proposals page of this web site, as well as your Reflection: Reviewing Sample Proposals journal for ideas, before you begin writing your own.
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