What are study limitations?
Every study has limitations. Study limitations can exist due to constraints on research design or methodology, and these factors may impact the findings of your study. However, researchers are often reluctant to discuss the limitations of their study in their papers, feeling that bringing up limitations may undermine its research value in the eyes of readers and reviewers.
In spite of the impact it might have (and perhaps because of it) you should clearly acknowledge any limitations in your research paper in order to show readers—whether journal editors, other researchers, or the general public—that you are aware of these limitations and to explain how they affect the conclusions that can be drawn from the research.
In this article, we provide some guidelines for writing about research limitations, show examples of some frequently seen limitations, and recommend techniques for presenting this information. And after you have finished drafting and revising your research paper manuscript, you still might want to follow this up with academic editing before submitting your work to your target journal.
Why do I need to include limitations in my research paper?
Although limitations address the potential weaknesses of a study, writing about them towards the end of your paper actually strengthens your study by identifying any problems before other researchers or reviewers find them. Furthermore, pointing out study limitations shows that you’ve considered the impact of research weakness thoroughly and have an in-depth understanding of your research topic. Since all studies face limitations, being honest and detailing these limitations will impress researchers and reviewers more than ignoring them.
Where should I put the limitations in my paper?
Some limitations might be evident to researchers before the start of the study, while others might become clear while you are conducting the research. Whether these limitations are anticipated or not, and whether they are due to research design or to methodology, they should be clearly identified and discussed in the discussion section—the final section of your paper. Most journals now require you to include a discussion of potential limitations of your work and many ask you to place this “limitations section” at the very end of your article. Some journals ask you to also discuss the strengths of your work in this section, and some allow you to freely choose where to include that information in your discussion section—make sure to always check the author instructions of your target journal before you finalize a manuscript and submit it for peer review.
What kinds of study limitations exist?
There are several reasons why study limitations might exist. The two main categories of limitations are those that result from the methodology and those that result from issues with the researcher(s).
Common methodological limitations
Limitations due to methodological problems can be addressed by clearly and directly identifying the potential problem and suggesting ways in which this could have been addressed—and SHOULD be addressed in future studies. The following are some major potential methodological issues that can impact the conclusions researchers can draw from the research.
Issues with samples and selection
Sampling errors occur when a probability sampling method is used to select a sample, but that sample does not reflect the general population or appropriate population concerned. This results in limitations for your study known as “sample bias” or “selection bias.” For example, if you conducted a survey to obtain your research results, your samples (participants) were asked to respond to the survey questions. However, you might have had limited ability to gain access to the appropriate type or geographic scope of participants. In this case, the people who responded to your survey questions may not truly be a random sample.
Insufficient sample size for statistical measurements
When conducting a study, it is important to have a sufficient sample size in order to draw valid conclusions. The larger the sample, the more precise your results will be. If your sample size is too small, it will be difficult to identify significant relationships in the data.
Normally, statistical tests require a larger sample size to ensure that the sample is considered representative of a population and that the statistical result can be generalized to a larger population. It is a good idea to understand how to choose an appropriate sample size before you conduct your research by using scientific calculation tools—in fact, many journals now require such an estimation to be included in every manuscript that is sent out for review.
Lack of previous research studies on the topic
Citing and referencing prior research studies constitutes the basis of the literature review for your thesis or study, and these prior studies provide the theoretical foundations for the research question you are investigating. However, depending on the scope of your research topic, prior research studies that are relevant to your thesis might be limited.
When there is very little or no prior research on a specific topic, you may need to develop an entirely new research typology. In this case, discovering a limitation can be considered an important opportunity to identify literature gaps and to present the need for further development in the area of study.
Methods/instruments/techniques used to collect the data
After you complete your analysis of the research findings (in the discussion section), you might realize that the manner in which you have collected the data or the ways in which you have measured variables has limited your ability to conduct a thorough analysis of the results. For example, you might realize that you should have addressed your survey questions from another viable perspective, or that you were not able to include an important question in the survey. In these cases, you should acknowledge the deficiency or deficiencies by stating a need for future researchers to revise their specific methods for collecting data that includes these missing elements.
Common limitations of the researcher(s)
Limitations that arise from situations relating to the researcher or researchers (whether the direct fault of the individuals or not) should also be addressed and dealt with, and remedies to decrease these limitations—both hypothetically in your study and practically in future studies—should be proposed.
Limited access to data
If your research involved surveying certain people or organizations, you might have faced the problem of having limited access to these respondents. Due to this limited access, you might need to redesign or restructure your research in a different way. In this case, explain the reasons for limited access and be sure that your finding is still reliable and valid despite this limitation.
Just as students have deadlines to turn in their class papers, academic researchers might also have to meet deadlines for submitting a manuscript to a journal or face other time constraints related to their research (e.g., participants are only available during a certain period; funding runs out; collaborators move to a new institution). The time available to study a research problem and to measure change over time might be constrained by such practical issues. If time constraints negatively impacted your study in any way, acknowledge this impact by mentioning a need for a future study (e.g., a longitudinal study) to answer this research problem.
Conflicts arising from cultural bias and other personal issues
Researchers might hold biased views due to their cultural backgrounds or perspectives of certain phenomena, and this can affect a study’s legitimacy. Also, it is possible that researchers will have biases toward data and results that only support their hypotheses or arguments. In order to avoid these problems, the author(s) of a study should examine whether the way the problem was stated and the data-gathering process were carried out appropriately.
Steps for organizing your imitations section
When you discuss study limitations, don’t simply list and describe your limitations—explain how these limitations have influenced your research findings. There might be multiple limitations in your study, but you only need to point out and explain those that directly relate to and impact how you address your research questions.
We suggest that you divide your limitations section into three steps: (1) identify the limitations; (2) explain how they impact your study; and (3) propose a direction for future studies and present alternatives. By following this sequence when discussing your study’s limitations, you will be able to clearly demonstrate your study’s weakness without undermining the quality and integrity of your research.
Step 1. Identify the limitation(s)
- This part should comprise around 10%-20% of your discussion of limitations.
The first step is to identify the particular limitation(s) that affected your study. There are many possible research limitations that can affect your study, but you don’t need to write a long review of all possible limitations. A 200-500 word critique is an appropriate length for a research limitations section. In the beginning of this section, identify what limitations your study has faced and how important these limitations are.
You only need to identify limitations that had the greatest potential impact on: (1) the quality of your findings, and (2) your ability to answer your research question. Step 1: Identify and describe the limitation. Here, the model’s estimates are based on potentially biased observational studies.
Step 2. Explain these limitations in detail
- This part should comprise around 60-70% of your discussion of limitations.
After identifying your research limitations, it’s time to explain the nature of the limitations and how they potentially impacted your study. For example, when you conduct quantitative research, a lack of probability sampling is an important issue that you should mention. On the other hand, when you conduct qualitative research, the inability to generalize the research findings could be an issue that deserves mention.
Explain the role these limitations played on the results and implications of the research and justify the choice you made in using this “limiting” methodology or other action in your research. Also, make sure that these limitations didn’t undermine the quality of your dissertation. Step 2: Explain the limitations in detail and the potential impact. These limitations can be broken down into several subsections, as seen in this example.
Step 3. Propose a direction for future studies and present alternatives (optional)
- This part should comprise around 10-20% of your discussion of limitations.
After acknowledging your limitations, you need to discuss some possible ways to overcome these limitations in future studies. One way to do this is to present alternative methodologies and ways to avoid issues with, or “fill in the gaps of” the limitations of this study you have presented. Discuss both the pros and cons of these alternatives and clearly explain why researchers should choose these approaches. Make sure you are current on approaches used by prior studies and the impacts they have had on their findings. Cite review articles or scientific bodies that have recommended these approaches and why. This might be evidence in support of the approach you chose, or it might be the reason you consider your choices to be limitations. This process can act as a justification for your approach and a defense of your decision to take it while acknowledging the feasibility of other approaches.
Common phrases used to start your limitations section
The following phrases are frequently used to introduce study limitations:
- “There may be some possible limitations in this study.”
- “The findings of this study have to be seen in light of some limitations.”
- “The first is the…The second limitation concerns the…”
- “The empirical results reported herein should be considered in the light of some limitations.”
- “This research, however, is subject to several limitations.”
- “The primary limitation to the generalization of these results is…”
- “Nonetheless, these results must be interpreted with caution and a number of limitations should be borne in mind.”
- “As with the majority of studies, the design of the current study is subject to limitations.”
- “There are two major limitations in this study that could be addressed in future research. First, the study focused on …. Second ….”
For more articles on research writing and the journal submissions and publication process, visit Wordvice’s Academic Resources page.
And be sure to receive professional English editing and proofreading services for your journal manuscript before submitting it to journal editors.
- FREE Citation Machine (APA, MLA, Chicago, Vancouver)
- Proofreading & Editing Guide
- Writing the Results Section for a Research Paper
- How to Write a Literature Review
- Research Writing Tips: How to Draft a Powerful Discussion Section
- How to Captivate Journal Readers with a Strong Introduction
- Tips That Will Make Your Abstract a Success!
- APA In-Text Citation Guide for Research Writing
- Diving Deeper into Limitations and Delimitations (PhD student)
- Organizing Your Social Sciences Research Paper: Limitations of the Study (USC Library)
- Research Limitations (Research Methodology)
- Sample Size Calculation (US National Library of Medicine)
- How to Present Limitations and Alternatives (UMASS)
Pearson-Stuttard, J., Kypridemos, C., Collins, B., Mozaffarian, D., Huang, Y., Bandosz, P.,…Micha, R. (2018). Estimating the health and economic effects of the proposed US Food and Drug Administration voluntary sodium reformulation: Microsimulation cost-effectiveness analysis. PLOS. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002551
Xu, W.L, Pedersen, N.L., Keller, L., Kalpouzos, G., Wang, H.X., Graff, C,. Fratiglioni, L. (2015). HHEX_23 AA Genotype Exacerbates Effect of Diabetes on Dementia and Alzheimer Disease: A Population-Based Longitudinal Study. PLOS. Retrieved from https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1001853