ENTREQ

What it is

ENTREQ (Enhancing Transparency in Reporting the Synthesis of Qualitative Research) is a reporting guideline — a 21-item checklist organized into five domains (introduction, methods and methodology, literature search and selection, appraisal, and synthesis of findings) — published by Tong, Flemming, McInnes, Oliver, and Craig in BMC Medical Research Methodology in 2012 and indexed on the EQUATOR Network. Its purpose is to make the process of synthesizing primary qualitative studies transparent and reproducible: how the review question was framed, how qualitative studies were searched and selected, how (and whether) their quality was appraised, and — the part most often left opaque — how primary findings were coded, compared, and transformed into higher-order interpretive themes. ENTREQ is method-agnostic across the qualitative synthesis family: it applies whether the synthesis approach is meta-ethnography, thematic synthesis, framework synthesis, meta-aggregation, grounded-theory synthesis, or critical interpretive synthesis. It is maintained as a community reporting standard rather than by a regulatory agency.

When to use

Use ENTREQ when the deliverable is a synthesis of primary qualitative research and you need a transparent reporting backbone — a peer-reviewed journal manuscript, a protocol, or the qualitative-evidence section of an HTA patient-input submission. In HEOR/RWE this is the qualitative arm of the evidence base: syntheses of patient and caregiver experience of treatment burden, illness and symptom experience, barriers and facilitators to adherence, acceptability of an intervention, or the lived-experience evidence that anchors PRO instrument content and value frameworks. Decision rule for which guideline applies: if you are synthesizing qualitative studies, ENTREQ is the umbrella reporting standard; if the synthesis method is specifically meta-ethnography (Noblit & Hare), the purpose-built extension eMERGe (France et al., 2019) is more granular and is the right choice. If you are reporting a synthesis of quantitative (RCT or observational) studies, ENTREQ is the wrong family — use PRISMA 2020 and, for protocols, PRISMA-P. For mixed-methods reviews, ENTREQ governs the qualitative strand while a PRISMA-family statement governs the quantitative strand.

What it requires

ENTREQ enforces explicit reporting across its five domains. (1) Introduction — a clear qualitative review aim. (2) Methods/methodology — the synthesis methodology and the epistemological/theoretical approach stated up front, plus the reviewers' role and reflexivity. (3) Literature search and selection — search strategy, sources, the sampling approach (exhaustive vs purposive/theoretical sampling, which is legitimate and even preferred in qualitative synthesis), inclusion/exclusion rationale, and a documented selection process. (4) Appraisal — whether and how the quality of included studies was assessed and what was done with that assessment (note: ENTREQ reports that appraisal happened; it does not itself appraise). (5) Synthesis of findings — how data were extracted, the software used, the coding and comparison process, how themes were derived (data-driven vs theory-driven), how primary-author quotations are distinguished from reviewers' interpretations, and the audit trail from raw quotations to third-order constructs. The throughline is interpretive traceability: a reader should be able to follow each synthesized theme back to the primary data that produced it.

When NOT to use — limitations and common misapplications

ENTREQ is a reporting checklist; it is not a risk-of-bias instrument and not a quality score. Completing it tells the reader what you did, not whether the synthesis was done well — for critical appraisal of the included qualitative studies use CASP, JBI, or an equivalent tool, and do not confuse a fully ticked ENTREQ checklist with methodological rigor (checklist-as-theater). Concrete failure modes: (a) wrong extension for the design — applying generic ENTREQ when the method is meta-ethnography and the more specific eMERGe guidance exists, or — conversely — forcing ENTREQ onto a quantitative review where PRISMA is required; (b) treating it as a conduct guide — ENTREQ does not tell you how to perform meta-ethnography, only how to report it; (c) using ENTREQ to lend false rigor to a thin synthesis with few primary studies or no audit trail; (d) applying it to a single primary qualitative study (where COREQ or SRQR is the relevant standard) rather than to a synthesis of studies. ENTREQ also predates GRADE-CERQual, which assesses confidence in qualitative synthesis findings — ENTREQ reports the synthesis; CERQual rates how much to trust each finding, and the two are complementary, not interchangeable.

How it maps to this catalog

ENTREQ is the reporting envelope for the catalog's qualitative and patient-experience concepts. The synthesis itself is implemented by `qualitative-synthesis`; the primary studies it ingests are described by `qualitative-interview` and `qualitative-ethnographic`; when the qualitative strand sits inside a broader design, `mixed-methods` is the integrating frame. ENTREQ's domains directly support the patient-experience evidence used in `pro-development`, `pro-validation`, and `pro-rwe` (a transparent synthesis of lived-experience studies is how PRO item content and conceptual frameworks are justified for FDA PFDD and for HTA value cases). For where ENTREQ sits relative to its quantitative siblings, see `systematic-review` and `scoping-review` (and PRISMA/PRISMA-P in the guideline set). Applied note for claims/EHR/registry RWE: ENTREQ does not touch phenotype algorithms, time-zero, confounding control, or attrition — those belong to the quantitative concepts. Its role in a claims/EHR/registry program is the qualitative complement: when a mixed-methods HEOR study pairs a claims-based treatment-pattern or cost analysis with a synthesis of patient-experience studies (e.g., to explain why adherence breaks down, or to ground a treatment-burden endpoint), ENTREQ is the standard that keeps the qualitative half auditable while the quantitative half follows RECORD-PE/STROBE and the relevant design concepts.