Critical Appraisal Tools

“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).

Amanda Burls, Director of Postgraduate Programmes in Evidence-Based Health Care, University of Oxford

Bias can be introduced at any point in the research process, from study design to publication, and as such, there are many different forms of bias. (For descriptions and examples of forms of bias, see the University of Oxford’s Biases Archive). Bias or systemic error can lead to inaccurate or incomplete conclusions. Therefore it is imperative to assess possible sources of bias in the research you encounter.

Hundreds of critical appraisal tools (CATs) have been developed to help you do so. Rather than providing a comprehensive list, this page provides a short list of CATs recommended by expert review groups and health technology assessment organizations. The list is organized by study design.

Case Control

Clinical Prediction Rule




Economic Evaluations

Mixed Methods

Other Quantitative




Randomized Controlled Trials

Systematic Reviews

Reviews of Critical Appraisal Tools

This section lists articles which have reviewed or inventoried CATs. These articles can serve more comprehensive catalogs of previously developed CATs.

Buccheri RK, Sharifi C. Critical Appraisal Tools and Reporting Guidelines for Evidence-Based Practice. Worldviews Evid Based Nurs. 2017;14(6):463-472. doi:10.1111/wvn.12258

Munthe-Kaas HM, Glenton C, Booth A, Noyes J, Lewin S. Systematic mapping of existing tools to appraise methodological strengths and limitations of qualitative research: first stage in the development of the CAMELOT tool. BMC Med Res Methodol. 2019;19(1):113. doi:10.1186/s12874-019-0728-6

Quigley JM, Thompson JC, Halfpenny NJ, Scott DA. Critical appraisal of nonrandomized studies-A review of recommended and commonly used tools. J Eval Clin Pract. 2019;25(1):44-52. doi:10.1111/jep.12889