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Critical Appraisal: Evaluating Studies

Critical appraisal is the process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context (Burls, 2009). Critical appraisal of studies involves checking the quality, reliability and relevance of the studies you've selected to help answer your review question. Depending on the type of study you are evaluating you may use different evaluation tools. When evaluating studies, some questions to consider are:

  • ​​​​Has the study's aim been clearly stated?
  • Does the sample accurately reflect the population?
  • Has the sampling method and size been described and justified?
  • Have exclusions been stated?
  • Is the control group easily identified?
  • Is the loss to follow-up detailed?
  • Can the results be replicated?
  • Are there confounding factors?
  • Are the conclusions logical?
  • Can the results be extrapolated to other populations?

Adapted from: University of Illinois, Chicago Library



Burls, A. (2009). What is critical appraisal? Retrieved April 21, 2022, from

University of Illinois Chicago Library. (2023, December 15). Evidence Based Medicine


See chapters Finding the Evidence and Why Study Results Mislead

  • What is Critical Appraisal? An overview of critical appraisal by Amanda Burls, Director of the Critical Appraisal Skills Programme (CASP) Director of Postgraduate Programmes in Evidence-Based Health Care, University of Oxford.

Burls, A. (2009). What is critical appraisal? Retrieved April 21, 2022, from

More on Critical Appraisal

Tod, D., Booth, A., & Smith, B. (2021). Critical appraisal. International Review of Sport and Exercise Psychology, 1-21. This article helps to define critical appraisal, identify its benefits, discuss conceptual issues influencing the adequacy of a critical appraisal, and detail procedures to help reviewers undertake critical appraisals.

Buccheri, R. K., & Sharifi, C. (2017). Critical Appraisal Tools and Reporting Guidelines for Evidence‐Based Practice. Worldviews on Evidence-Based Nursing, 14(6), 463–472.  The primary purpose of this paper is to help nurses understand the difference between critical appraisal tools and reporting guidelines.


Selected critical Appraisal Tools