Critical appraisal (also known as quality assessment) involves checking the quality, reliability and relevance of the studies being screened in relation to the review question. There are several tools used for quality assessment or critical appraisal of studies included in an evidence synthesis review. The choice of tool depends on the type of study and research question.  Some examples are listed below:

Cochrane Risk of Bias (RoB) tool: This tool is used to assess the risk of bias in randomized controlled trials (RCTs) included in a systematic review. The RoB tool considers domains such as sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other sources of bias. 

Grading of Recommendations, Assessment, Development, and Evaluation (GRADE): GRADE is used to judge a body of evidence as a whole such as rating recommendations in clinical guidelines or policies. 

Newcastle-Ottawa Scale (NOS): NOS is used to assess the quality of observational studies included in a systematic review. The NOS tool assesses the quality of studies based on three domains: selection of study groups, comparability of groups, and ascertainment of outcomes. 

Jadad scale: This tool is also used to assess the quality of RCTs included in a systematic review. The Jadad scale assesses the quality of studies based on three domains: randomization, blinding, and withdrawals and dropouts. 

Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I): This tool is used to assess the risk of bias in non-randomized studies included in a systematic review.  ROBINS-I assesses the quality of studies based on seven domains: confounding, selection of participants, classification of interventions, deviations from intended interventions, missing data, measurement of outcomes, and selection of the reported results. 

Additional tools for critical appraisal can be found at the Joanna Briggs Institute website. Tutorials for critical appraisal can be found in the Critical Appraisal Tutorials library guide.

You can seek advice from experts, such as your principal investigator or course instructor, to determine the most suitable tool for evaluating the type of study being evaluated. 

For more advanced inquiries regarding quality assessment, please reach out to Matthew Mitchell at the Penn Medicine Center for Evidence-based Practice (Matthew.Mitchell2@pennmedicine.upenn.edu).