CASP Randomised Controlled Trial Checklist
Critical Appraisal Skills Programme Randomised Controlled Trial Checklist · Also known as: CASP-RCT, CASP
The Critical Appraisal Skills Programme (CASP) RCT Checklist is a practical, widely adopted tool developed by the UK-based Critical Appraisal Skills Programme (founded 1993) for assessing the methodological quality and relevance of published randomized controlled trials. Unlike numeric scoring scales, it uses 11 structured questions with yes/no/cannot tell responses to guide critical appraisal in a format accessible to busy clinicians, researchers, and educators.
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When to use it
CASP RCT Checklist is suitable for busy practitioners, students, and research teams learning critical appraisal. Use in teaching settings, clinical guideline development, and systematic reviews when a pragmatic, accessible quality assessment tool is preferred over more detailed algorithms. Particularly valuable in resource-limited settings where comprehensive tools (e.g., Cochrane RoB 2) may be time-prohibitive.
Strengths & limitations
- Practical 11-item format is quick to administer (15–30 min) and accessible to non-specialists, making it ideal for teaching and clinical practice
- Explicit guidance for each question reduces ambiguity and improves inter-rater reliability compared to unstructured appraisal
- Yes/no/cannot tell structure emphasizes transparency; 'cannot tell' responses highlight reporting deficiencies without penalizing methodologically sound trials with sparse reporting
- Focus on core design principles (randomization, allocation concealment, blinding, follow-up) aligns with modern evidence standards and Cochrane RoB 2 domains
- Qualitative interpretation encourages nuanced judgment; no false precision from summing scores across heterogeneous items
- Lack of a summary score or categorical judgment (low/moderate/high risk) makes ranking studies in systematic reviews less straightforward than quantitative tools
- No explicit domain-specific algorithms for different trial designs (e.g., crossover, cluster-randomized); some designs may not fit the 11-item framework well
- Checklist does not address outcome reporting bias or selective publication; assessment is limited to internal validity
- Inter-rater agreement statistics (kappa, ICC) are not routinely reported in CASP guidance; reliability varies by reviewer experience
- CASP tools exist for multiple study designs (RCT, cohort, case-control, systematic review, qualitative), which may lead to confusion regarding which version to use
Frequently asked
Should I sum up 'yes' responses to get a total quality score?
No. CASP guidance explicitly advises against summing responses into a single score. Instead, review the pattern of answers to identify key strengths and limitations. For example, a trial with strong randomization and allocation concealment but incomplete follow-up has different strengths and risks than a trial with weak randomization but complete follow-up. Interpret qualitatively.
What does a 'cannot tell' answer mean, and should I exclude such trials?
'Cannot tell' means the report does not provide enough information to answer the question; it does not necessarily mean the trial was poorly conducted. Methodologically sound trials, especially older ones, often have sparse reporting. Contact trial authors to clarify methodology. Excluding all 'cannot tell' trials would bias your systematic review toward recent, well-reported studies.
How do I use CASP for systematic reviews?
Assign two independent reviewers to appraise each trial using the checklist. Reconcile disagreements by discussion or third-party arbitration. Document the results in a summary table or risk of bias chart (e.g., traffic light plot). In your meta-analysis, conduct sensitivity analyses (e.g., main analysis plus analysis excluding low-quality trials) to test robustness.
Can I use the CASP RCT checklist for cluster-randomized trials or crossover designs?
The standard checklist works for simple parallel-group RCTs. For cluster-randomized or crossover trials, you may need to adapt items (e.g., question on randomization unit). Consult CASP supplementary guidance or use Cochrane RoB 2, which includes domain-specific algorithms for these designs.
Is CASP suitable for rapid evidence reviews or scoping reviews?
Yes. CASP RCT checklist is efficient (15–30 min per trial) and pragmatic, making it suitable for rapid reviews with tight timelines. However, for comprehensive systematic reviews requiring detailed quality assessment and sensitivity analyses, Cochrane RoB 2 may provide more granular information.
Sources
- Critical Appraisal Skills Programme (CASP). (1993, updated). CASP Randomised Controlled Trials Checklist. University of Oxford, UK. www.casp-uk.net link ↗
How to cite this page
ScholarGate. (2026, June 3). Critical Appraisal Skills Programme Randomised Controlled Trial Checklist. ScholarGate. https://scholargate.app/en/research-methodology/casp-rct-checklist
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