Free research tool
Free CASP-Style Critical Appraisal Checklist
Work through structured appraisal questions for randomised controlled trials, qualitative studies, cohort studies and systematic reviews.
This is an original study-appraisal companion and not the official CASP checklist.
Research focus
Is the research aim or question clearly stated?
Look for a clear description of what the study is trying to investigate.
Study design
Is the chosen study design appropriate for the research question?
Consider whether the design can reasonably address the stated aim.
Participants and sampling
Is the participant selection or sampling approach appropriate?
Consider recruitment, inclusion criteria, representativeness and possible selection bias.
Data collection
Are the data collection methods clearly described and suitable?
Check whether the methods are appropriate, consistent and sufficiently explained.
Bias and limitations
Have important sources of bias or methodological limitation been considered?
Look for selection bias, measurement bias, confounding and other threats to validity.
Findings
Are the main findings clearly presented and supported by the data?
Check whether conclusions are consistent with the results actually reported.
Confidence in findings
Is there enough information to judge confidence in the findings?
Consider uncertainty, precision, consistency, credibility and completeness of reporting.
Applicability
Can the findings reasonably be applied beyond the study sample or setting?
Consider population, setting, context and how closely they match the situation of interest.
Research value
Does the study make a useful contribution to the evidence base?
Consider relevance, originality, implications and how the study fits with other evidence.
Randomisation
Was allocation to study groups carried out using an appropriate random process?
Consider how the allocation sequence was generated and whether allocation could have been predicted.
Group comparability
Were the groups sufficiently similar at the start of the study?
Look for important baseline differences that could affect interpretation of the outcome.
Blinding
Were reasonable steps taken to reduce knowledge of group allocation where possible?
Consider participants, clinicians and outcome assessors, while recognising that blinding is not always feasible.
What is critical appraisal?
Critical appraisal helps you judge whether research methods, findings and conclusions are sufficiently trustworthy and relevant for your academic question or practice context.
Assess methodology
Examine study design, sampling, data collection and analysis.
Consider bias
Identify limitations, confounding and other threats to the credibility of the findings.
Judge applicability
Decide how relevant the findings are to your population, setting and research question.
Study designs supported
Randomised controlled trials
Review randomisation, baseline group comparability, blinding, outcome measurement and confidence in the results.
Qualitative studies
Consider methodological fit, sampling, researcher influence, qualitative analysis and credibility of interpretations.
Cohort studies
Examine exposure and outcome measurement, confounding, participant selection and applicability of associations.
Systematic reviews
Evaluate the search strategy, eligibility criteria, quality assessment and appropriateness of the evidence synthesis.
Critical appraisal FAQs
What is critical appraisal?
Critical appraisal is the structured evaluation of research methods, findings, limitations, relevance and trustworthiness.
Is this the official CASP checklist?
No. This tool uses original wording based on broad evidence-appraisal principles. If your university requires a specific CASP checklist, use the official version required by your course.
Should I calculate a score from critical appraisal?
Not necessarily. The Yes, No and Unclear counts in this tool help you track your appraisal, but methodological quality should be interpreted by considering the importance of each issue rather than relying on a simple numerical score alone.
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