Critical appraisal is the process of carefully and systematically assessing the outcome of scientific research (evidence) to judge its trustworthiness, value and relevance in a particular context. Critical appraisal looks at the way a study is conducted and examines factors such as internal validity, generalizability and relevance.
Some initial appraisal questions you could ask are:
1. Is the evidence from a known, reputable source?
2. Has the evidence been evaluated in any way? If so, how and by whom?
3. How up-to-date is the evidence?
Second, you could look at the study itself and ask the following general appraisal questions:
1. Did the study address a clearly focused issue?
2. Is the study design appropriate to the stated aims?
3. Are the measurements likely to be valid and reliable?
4. Are the statistical methods described?
5. How large was the effect size?
6. How precise was the estimate of the effect (look for the confidence intervals!)
7. Could there be confounding?
8. What implications does the study have for your practice? Is it relevant?
9. Can the results be applied to your organization?
10. Is the intervention feasible in your organization?
If you would like to critically appraise a study, we strongly recommend using the app we have developped for Iphone and Android: CAT Manager App
You could also consider using the following appraisal questionnaires (checklists) for specific study designs, but we do not recommend this.