Basics of Systematic Reviews

A guide to evidence synthesis

Step 6: Assess the Quality of Included Studies (Bias Assessment/Critical Appraisal)

After determining which studies will be included, your team will need to evaluate the evidence for its validity, relevance, and applicability. This step involves using a quality assessment tool to check primary empirical studies for any flaws in methodology, as well as any other sources of bias.

Step 6a: Choose a Quality Assessment Tool

Also known as quality appraisal, critical appraisal, and risk of bias assessment, quality assessment tools are essentially questionnaires designed to help a research team assess the quality of various study designs. The questionnaire will be customized to ask specific questions about the methodology of a study according to its category. Appraisal tools exist for most types of study designs. Be sure to select a quality assessment tool that aligns with the study types you anticipate will appear in your results.

You can find a repository of Quality Assessment Tools through OSF, which allows you to filter by study type and intended use. We also highly recommend UNC Libraries' list of quality assessment tools:

Quality Assessment and Risk of Bias Tool Repository
A resource for finding and selecting a risk of bias or quality assessment tool for evidence synthesis projects. This project was created and is maintained by Duke University's Medical Center Library & Archives.
What Quality Assessment Tool Should I Use?
This page features a comprehensive list of quality assessment/risk of bias tools from UNC Libraries organized by study type.

Video Tutorials

Critical Appraisal/Bias Assessment in the Health Professions: