Strata Academy

CASP checklists explained – critical appraisal skills for students

Design-specific CASP tools, reporting clarity vs risk of bias, and when CASP complements ROB 2 or JBI

1. What is CASP?

CASP (Critical Appraisal Skills Programme) provides free checklists to help healthcare professionals appraise research evidence. Tools exist for RCTs, systematic reviews, cohort studies, case–control studies, qualitative studies, economic evaluations, and diagnostic studies.

CASP was designed for teaching – questions are plain language and organised for discussion in small groups. Items are not identical to Cochrane ROB 2 signalling questions or AMSTAR 2 critical domains.

Each checklist is a PDF worksheet with space for notes. Students often complete CASP in journal club before writing a fuller appraisal with design-specific bias tools.

CASP is widely used in UK medical schools because it lowers the barrier to structured reading without requiring Cochrane training first.

2. Reporting clarity vs risk of bias

CASP questions often address whether the study addressed a focused question, whether methods were valid for the design, and whether results are applicable to your patients.

A 'yes' on a CASP validity question does not automatically mean low risk of bias under ROB 2 – CASP blends clarity, face validity, and bias concepts in one educational flow.

Treat CASP as a structured reading guide. For formal systematic reviews, intercalated dissertations, or guideline work, pair CASP learning with official tools where examiners require them.

When CASP asks about sample size, link to power and precision concepts – a justified sample size can still produce imprecise results if event rates were wrong.

3. CASP by study design

Selecting the wrong CASP checklist is a common journal-club error – read the methods section before downloading the form.

RCT papers use the CASP RCT checklist; combine with ROB 2 when you need domain-level bias judgements for coursework.

Systematic reviews use the CASP SR checklist; add AMSTAR 2 for methodological quality and PRISMA for reporting completeness.

Diagnostic papers use the CASP diagnostic checklist alongside QUADAS-2 and our diagnostic statistics guide.

• RCT → CASP RCT checklist + ROB 2 for formal bias domains
• Systematic review → CASP SR checklist + AMSTAR 2 / PRISMA
• Cohort → CASP cohort checklist + ROBINS-I if non-randomised intervention
• Qualitative → CASP qualitative checklist (credibility, transferability)
• Diagnostic → CASP diagnostic checklist + QUADAS-2

4. CASP's three-section structure

Most CASP tools organise questions into: (1) Is the study valid? (2) What are the results? (3) Are the results useful locally?

Section 1 maps loosely to internal validity and methods transparency. Section 2 forces you to extract effect sizes, CIs, and precision – not only p-values.

Section 3 pushes applicability – often skipped by students but valued in clinical teaching. Ask whether the enrolled spectrum matches your ward or clinic.

Strong journal club facilitators spend equal time on sections 2 and 3, not only ticking section 1.

5. Limitations of CASP alone

CASP does not replace Cochrane risk-of-bias algorithms for meta-analysis or GRADE certainty ratings.

Checklist answers may be subjective without signalling-question discipline – two students can disagree on the same item without citing text.

For intercal dissertations, supervisors may require ROB 2, ROBINS-I, or AMSTAR 2 even if you learned with CASP.

CASP is not a reporting guideline – use CONSORT, STROBE, or PRISMA when assessing whether authors reported enough to reproduce the study.

6. CASP and StrataResearch

StrataResearch uses CASP concepts for reporting-clarity layers while applying design-specific bias frameworks (ROB 2, JBI, QUADAS-2, etc.) for domain scoring.

Upload a paper via quick analysis and compare automated feedback to your CASP worksheet – gaps often appear in statistics reporting or limitations sections.

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