What is a Critical Appraisal?
Written by Cindy Zhang
What is a critical appraisal...in simple terms?
Critical appraisal is the process of systematically examining research to judge its trustworthiness, and its value and relevance in a particular context (Morrison, 2017). In other words, it is the process of looking at a study through the eyes of an evaluator. Although we look to papers for information, we cannot trust them completely - even those published in the most prestigious journals. It is important that we look at a paper critically so that we can identify its strengths and weaknesses. Perhaps there is a limitation to a certain methodology used or there is an alternate explanation for the results that the researchers did not cover. These are all things to look for in a critical appraisal.
Critical appraisal is a crucial skill in scientific research. Being able to look at a study critically allows you to assess the validity of the information that you are presented with. For example, if you were doing a research assignment in school, you would need to know whether a study can be considered reliable. Or if you were writing a systematic review, you would need to critically appraise each of the studies that you select, and this involves a more formal process.
What does it look like?
A critical appraisal can come in many forms, and this depends on the type of study that you are looking at. A clinical trial that follows human participants would provide different things to look at than a study using animal models. In a clinical study, some things to consider are the recruitment of subjects (whether the sample size is defined and justified, whether participants are representative of the whole population), how outcome factors are measured (whether all outcomes are measured, if any confounding variables are accounted for), and how the data is interpreted and presented (whether the appropriate statistical tests were used) (Al-Jundi & Sakka, 2017). These are just some of the questions that can be asked in a critical appraisal, and they would often be presented in the form of a checklist. This is a way of documenting your critical appraisal process and making it transparent and easy to follow for someone else. Here is a simplified version of the checklist that you can apply to clinical studies:
(Al-Jundi & Sakka, 2017)
What to include
Although the format of your critical appraisal will vary depending on the type of study, there are some broad elements that are found in any critical appraisal. First, the validity or trustworthiness of the methodology is analyzed. In this section, you can analyze the participant selection process in a case study, look at risk of bias in a survey study, or point out the technical limitations of lab techniques in a non-clinical study. There are numerous factors to consider and your goal is to determine whether the researchers have addressed their research question in a reliable manner.
Second, the value and relevance of the study is evaluated. The key question to ask here is: what are the gaps in research in this area of research and what are the implications of the study’s findings? It is important to situate a study within the context of what is already known and determine what new information it adds to the existing knowledge in its field.
Conclusion
A critical appraisal can take on many forms depending on the type of study being analyzed, but they can all give you insight on the quality of the study and enrich your understanding. Mastering the process of critical appraisal allows you to think critically about the information that you read.
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Al-Jundi, A., & Sakka, S. (2017). Critical appraisal of Clinical Research. JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH. https://doi.org/10.7860/jcdr/2017/26047.9942
Morrison, K. (2019, May 13). Dissecting the literature: The importance of critical appraisal. Royal College of Surgeons. Retrieved October 13, 2021, from https://www.rcseng.ac.uk/library-and-publications/library/blog/dissecting-the-literature-the-importance-of-critical-appraisal/.
