Critical thinking

Critical appraisal is a specific aspect of critical analysis where you examine and assess research in order to judge its:

• Trustworthiness
• Value
• Relevance

You are evaluating the quality of the research and how it has been carried out, as well as the findings.

What you can choose to appraise will differ depending on the research methodology of the article and your field, so the suggestions below are general guidelines. Further down the page is a list of critical appraisal tools which are organised by and tailored to different types of research methodology.

• Introduction - are there clear aims and objectives? Is the research question clear and focused?
• Study design/choice of methodology - are they appropriate for what is being measured? Could the hypotheses/aim have been investigated using a different method?
• Methodology - are there methodological protocols to limit bias? Have participants been appropriately selected? Is the sample size appropriate? Have they followed any protocols for data collection and performing the study?
• Results and Statistical analysis - is raw data included? Have the findings been analysed accurately? Is there any potential measurement error? Has the reliability been considered? Is statistical significance considered?
• Discussion/interpretation of results - are these linked back to the study aims? Have null findings been interpreted? Have limitations of the study been considered? Are conclusions/arguments justified by the results data?
• External validity - can the results be generalised? Are the findings transferable to other settings or limited to the one where they were obtained?
• Bias - design, sampling, data collection, measurement, reporting, analysis, publication, ethical issues. Has potential bias been addressed? Are conflicts of interest addressed? 

Below is a suggested list of critical appraisal tools, which are checklists organised primarily by type of study, to help you identify what to critically appraise when reading a research article.These are primarily tailored to healthcare research but the principals can be adapted to other fields.

CASP (Critical Appraisal Skills Programme)

SIGN (Scottish Intercollegiate Guidelines Network)

Joanna Briggs Institute 

Specialist Unit for Review Evidence (Cardiff University)

Centre for Evidence-Based Medicine (University of Oxford)