JBI Critical Appraisal Checklist for Case Series

What it is

The JBI Critical Appraisal Checklist for Case Series is one of the family of design-specific critical-appraisal tools maintained by the Joanna Briggs Institute (JBI) as part of the JBI Manual for Evidence Synthesis. A case series is a descriptive study that reports a group of patients with the same exposure, condition, or intervention but without a comparator group — it sits at the lower end of the evidence hierarchy and cannot, by design, estimate a causal effect. The JBI checklist comprises 10 questions answered Yes / No / Unclear / Not applicable, covering: (1) clear inclusion criteria; (2) valid and reliable measurement of the condition for all participants; (3) valid identification methods for the condition; (4) consecutive inclusion of participants; (5) complete inclusion of participants; (6) clear reporting of demographics; (7) clear reporting of clinical information; (8) reporting of outcomes or follow-up results; (9) clear reporting of presenting site(s)/clinic(s) demographic information; and (10) appropriate statistical analysis. It is an appraisal (risk-of-bias-style) instrument that supports a transparent reviewer judgement about whether a series' findings are credible enough to inform a synthesis — it is explicitly not a numeric quality score and not a reporting guideline.

When to use

Reach for the JBI Case Series checklist when you are appraising the methodological quality of a no-comparator case series as part of a systematic review, scoping review, or evidence map (the dominant use case), or when a journal/editor asks for structured critical appraisal of a submitted series. It is the correct JBI instrument only when the design is a genuine case series: multiple patients, common exposure/condition, no control or comparison arm, and an aim that is descriptive (characterizing presentation, course, or short-term outcomes) rather than comparative. Decision rule for choosing among siblings: a single patient → JBI Case Reports checklist or the CARE reporting guideline; a series with no comparator → this checklist; the moment an internal or external comparison group is introduced, the design becomes a cohort or case-control study and you must appraise it with the JBI Cohort / Case-Control tools (and report it under STROBE, or RECORD/RECORD-PE for routinely collected health data). In HTA/payer contexts the checklist is useful for grading the certainty of descriptive real-world or single-arm safety evidence feeding an evidence dossier, where case series sometimes carry weight for rare diseases or novel exposures.

What it requires

Mapped to real-world data practice, the 10 items enforce: transparent eligibility (explicit, reproducible inclusion criteria rather than a convenience sample); valid and reliable ascertainment of the condition for every participant (a phenotype/algorithm question in claims/EHR work); valid identification methods (how the condition was confirmed — coded diagnosis, chart adjudication, laboratory confirmation); consecutive and complete inclusion (the central defense against selection bias in a series — were all eligible patients captured, or only the memorable ones?); complete demographic and clinical reporting; outcome/follow-up reporting with attention to who was lost; and appropriate statistical handling (descriptive statistics with uncertainty, not inferential claims a no-comparator design cannot support). For RWE the load-bearing items are consecutive/complete inclusion (selection bias), valid condition measurement (phenotype validity), and follow-up completeness (attrition).

When NOT to use — limitations and common misapplications

- It is an appraisal tool, not a reporting checklist. Do not use it to structure the write-up of a series; for reporting a single case use CARE, and for a series adapt CARE/STROBE elements (there is no dedicated EQUATOR statement for the case-series design). - It is not a quality score. Summing Yes answers into a number and thresholding ("7/10 = high quality") is a misuse JBI explicitly cautions against; the items inform a reasoned overall judgement. - Wrong tool for the design. A single patient is a case report (use the JBI Case Reports tool / CARE), not a case series. If a comparison group exists — even an external/historical control — the study is no longer a case series; appraise it as a cohort/case-control study (JBI Cohort/Case-Control + STROBE / RECORD-PE / HARPER for the analytic design). - Appraisal does not make a series causal. A flawless checklist score does not let a no-comparator series estimate a treatment effect, incidence rate ratio, or hazard ratio; without a comparator the design supports description and hypothesis generation only. - Checklist-as-theater. Pasting a completed grid into the appendix without using it to inform inclusion, sensitivity analyses, or certainty grading (e.g., GRADE) adds no value.

How it maps to this catalog

Each JBI item points to a concept in this repository that implements the underlying methodological requirement: - Inclusion criteria / consecutive & complete inclusion (items 1, 4, 5) → `descriptive-epidemiology-rwe`, `safety-signal-case-definition-rwe`, and `selection-bias-sensitivity-analysis-rwe` for diagnosing convenience-vs-consecutive sampling bias. - Valid measurement and identification of the condition (items 2, 3) → `diagnosis-phenotype-algorithm-1ip-2op-time-window-rwe`, `outcome-algorithm-construction-rwe`, and `algorithm-validation` (PPV/sensitivity of the case definition), with chart adjudication handled in `endpoint-adjudication-chart-review-rwe`. - Demographic and clinical reporting (items 6, 7, 9) → `baseline-characteristics-and-covariate-balance-rwe`. - Outcome and follow-up reporting (item 8) → `attrition-and-loss-to-follow-up-rwe` and `missing-data-pattern-table-rwe`. - Appropriate statistical analysis (item 10) → `descriptive-epidemiology-rwe` and `incidence-rate-calculation-rwe` for honest descriptive summaries; if a comparator is added the analysis moves into `target-trial-emulation`, `active-comparator-new-user`, and `estimands-ate-att-intercurrent-events-rwe` — and the appraisal tool changes accordingly.

Applied note (claims/EHR/registry RWE)

A claims- or EHR-derived "case series" of patients dispensed a new agent is only consecutive and complete if the data infrastructure captures all eligible patients with continuous observability — so items 4–5 become questions about `continuous-enrollment-observable-time-rwe` and `database-feasibility-attrition-funnel-rwe`. Item 2–3 (valid condition measurement) are answered by a validated phenotype rather than a clinician's note. Reviewers appraising registry case series should confirm whether enrollment was consecutive (population-based registry) or selective (referral/voluntary registry), because a convenience registry fails item 4 even when each record is well documented.