Strata Academy
CASP checklists explained – critical appraisal skills for students
Design-specific CASP tools, reporting clarity vs risk of bias, qualitative checklists, and when CASP complements ROB 2 or JBI
Quick answer
CASP provides free design-specific checklists for structured reading in journal club. Use CASP to learn appraisal logic, then pair with official bias tools (ROB 2, AMSTAR 2, QUADAS-2, JBI qualitative) for formal coursework and dissertations.
- CASP teaches structured reading — not a substitute for Cochrane ROB 2 or AMSTAR 2.
- Three sections: validity, results, local applicability — do not skip section 3.
- Pick the checklist that matches study design before you start ticking.
- Qualitative CASP focuses on credibility and transferability — not p-values.
- Pair CASP journal club with StrataResearch or ROB 2 assistant for RCT PDFs.
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. Oxford, Bristol, and many NHS trust journal clubs distribute CASP forms as default teaching material.
CASP Ltd is a not-for-profit programme. Checklists are updated periodically — download the current PDF from casp-uk.net rather than reusing outdated forms from older lecture slides.
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.
Examiners often reward students who cite text from the paper when answering CASP items. 'Yes' without a methods quote is weak evidence in viva or written coursework.
Tip: CASP 'was the sample size justified?' overlaps with statistical power concepts – see our sample size guide.
3. 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.
For qualitative CASP, section 2 emphasises themes and quotations; section 3 asks whether findings transfer to your service context.
| Section | Purpose | Common student error |
|---|---|---|
| 1 Validity | Methods fit the question; bias threats | Stopping after ticking without reading methods |
| 2 Results | Effect sizes, CIs, or thematic findings | Reporting p-value only for quantitative papers |
| 3 Applicability | Local relevance to your patients or service | Assuming positive trial = change practice tomorrow |
4. 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.
Economic evaluations have a dedicated CASP checklist — do not use the RCT form for cost-effectiveness models.
- RCT → CASP RCT checklist + ROB 2 for formal bias domains
- Systematic review → CASP SR checklist + AMSTAR 2 / PRISMA / ROBIS
- Cohort → CASP cohort checklist + ROBINS-I if non-randomised intervention
- Qualitative → CASP qualitative checklist (credibility, transferability)
- Diagnostic → CASP diagnostic checklist + QUADAS-2
5. CASP RCT checklist – high-yield items
The CASP RCT checklist walks through randomisation, blinding, follow-up, and statistical analysis in plain language. Items mirror concepts in ROB 2 Domains 1–4 but without signalling-question algorithms.
Randomisation: Was assignment truly random? Was allocation concealed? Could selection bias have occurred? These items align with ROB 2 Domain 1 but CASP does not require the official 'some concerns' algorithm.
Blinding: Who was blinded — participants, clinicians, outcome assessors? For subjective outcomes, unblinded assessment is a major validity threat even if randomisation was sound.
Follow-up: Were all participants accounted for? Differential loss between arms suggests missing-data bias — link to ROB 2 Domain 3.
Analysis: Was an intention-to-treat analysis performed? Per-protocol analysis alone can inflate apparent treatment effects when dropouts are related to side effects.
6. CASP qualitative checklist
The CASP qualitative tool asks whether the research aim was clear, whether qualitative methodology was appropriate, whether sampling and data collection were rigorous, and whether analysis was systematic.
Credibility items probe whether findings are supported by data — look for participant quotations, not author assertion alone. Transferability asks whether enough context is given for you to judge if findings might apply elsewhere.
CASP qualitative does not replace COREQ reporting assessment or JBI critical appraisal for qualitative synthesis. Use all three layers for dissertation depth: COREQ for reporting, CASP for teaching discussion, JBI for formal review work.
Common error: applying the RCT CASP form to an interview study because the journal title mentions 'patients'. Read the methods — if there is no randomisation, switch checklists.
- Was the research aim clear and appropriately qualitative?
- Was the recruitment strategy appropriate for the research aim?
- Were data collected in a way that addressed the research issue?
- Was the data analysis sufficiently rigorous?
- Is there a clear statement of findings and value for clinical practice?
Tip: See our qualitative appraisal guide for thematic analysis, trustworthiness, and COREQ reporting.
7. CASP systematic review checklist
The CASP SR checklist covers review question clarity, search comprehensiveness, study selection, appraisal of included studies, and whether results answer the review question.
Search: Did the search strategy include appropriate databases and avoid obvious gaps? CASP does not list every AMSTAR 2 critical flaw — but 'MEDLINE only' should trigger concern.
Selection: Was study selection duplicated? Single-reviewer screening is a process flaw that CASP and AMSTAR 2 both flag.
Synthesis: Were methods appropriate for the type of studies included? Narrative synthesis, meta-analysis, and GRADE require different scrutiny.
For coursework, completing CASP SR plus AMSTAR 2 critical items gives defensible depth without duplicating every question twice.
8. CASP in journal club – facilitator workflow
Allocate 45–60 minutes: 10 minutes silent reading, 25 minutes CASP sections 1–2 in pairs, 15 minutes section 3 applicability debate, 5 minutes action points.
Assign one student per CASP section as rapporteur — they must cite page numbers when defending yes/no answers.
End with one sentence: 'Would this paper change practice in our department?' Section 3 forces this explicitly; do not let the club end on statistics alone.
For mixed-methods papers, run two mini-CASP passes — quantitative and qualitative — rather than forcing one checklist.
- Confirm study design and download the matching CASP PDF
- Silent read of abstract, methods, results
- Pairs complete sections 1–2 with page citations
- Whole group debate section 3 applicability
- Optional: upload PDF to StrataResearch for framework-aligned domain scores
9. 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.
CASP does not produce traffic-light plots or domain-level algorithms — you cannot paste CASP answers directly into RevMan without translating to ROB 2.
10. Pairing CASP with official tools
Use CASP first in teaching settings; graduate to official tools for summative work. The mental model transfers — CASP 'validity' questions map to ROB 2 domains once you know the mapping.
RCT teaching path: CASP journal club → ROB 2 assistant tool → ROB 2 hub → StrataResearch PDF appraisal.
Systematic review path: CASP SR → PRISMA checklist tool → AMSTAR 2 hub → ROBIS for review-process bias.
Qualitative path: CASP qualitative → qualitative appraisal guide → Academy qualitative module → COREQ reporting check.
| Study type | CASP checklist | Official tool for formal work |
|---|---|---|
| RCT | CASP RCT | ROB 2 + CONSORT |
| Cohort intervention | CASP cohort | ROBINS-I + STROBE |
| Systematic review | CASP SR | AMSTAR 2 + PRISMA + ROBIS |
| Qualitative | CASP qualitative | JBI qualitative + COREQ |
| Diagnostic | CASP diagnostic | QUADAS-2 + STARD |
11. 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.
For RCTs, compare your CASP section 1 answers to StrataResearch ROB 2 domain output — disagreements usually trace to missing-data or selective reporting items students under-weight.
Frequently asked questions
Is CASP the same as ROB 2?
No. CASP is an educational checklist in plain language. ROB 2 is Cochrane's official risk-of-bias tool with signalling questions and domain algorithms for randomised trials.
Which CASP checklist for a qualitative interview study?
Use the CASP qualitative checklist — not the RCT or cohort forms. Pair with COREQ for reporting and our qualitative appraisal guide for methods depth.
Can I submit only CASP for my dissertation?
Depends on supervisor requirements. Many UK programmes expect ROB 2, ROBINS-I, AMSTAR 2, or JBI for summative appraisal even if you learned with CASP in journal club.
What is CASP section 3 for?
Applicability — whether results are useful for your local patients, service, or policy context. It prevents treating every positive trial as immediately practice-changing.
Where do I download CASP checklists?
Free PDFs from casp-uk.net. Always use the current version for your study design rather than outdated copies from lecture handouts.
Interactive walkthroughs and quizzes load when JavaScript is enabled — the checklist and tables above are fully readable without it.