Qualitative Evidence Synthesis: Choosing a Method and Reporting It with ENTREQ

Qualitative evidence synthesis (QES) brings together the findings of multiple qualitative studies to produce a new, higher-order interpretation — not a head-count of themes, but a synthesis that says something none of the individual studies said on their own. Unlike a systematic review of quantitative trials feeding a meta-analysis, QES works with interview transcripts, focus-group data and ethnographic accounts, and the synthesis method you pick shapes what kind of claim the review can actually make. Two decisions sit at the centre of doing this well: which synthesis approach fits your question, and how you report the process so a reader can judge how the findings were produced. This page covers both, using the ENTREQ statement as the reporting anchor.

What qualifies as qualitative evidence synthesis

QES is distinct from a single qualitative study (covered by COREQ or SRQR reporting, not ENTREQ) and from a narrative review that simply describes what studies found without a structured analytic process. It is also distinct from a scoping review, which maps the extent and nature of literature rather than synthesising findings into new interpretive claims. A QES takes qualitative findings that have already been published — the results sections of primary qualitative studies, not raw transcripts — and analyses them as its data, using one of several established synthesis methods.

Three synthesis approaches, and what each one is actually good for

The three most commonly used aggregative and interpretive approaches differ in philosophy, process and the kind of output they produce. A fourth, meta-ethnography, is covered in full in CASRAI’s separate guide to Noblit and Hare’s seven phases — it is the most purely interpretive, theory-generating option, and is only briefly distinguished here rather than repeated.

Thematic synthesis (Thomas & Harden, 2008)

Developed specifically for systematic reviews by adapting techniques from primary thematic analysis, thematic synthesis is the most widely used QES method. It runs in three stages: line-by-line free coding of the findings sections of included studies; organising those codes into descriptive themes that stay close to the original studies’ own language; and, as a distinct final step, generating analytical themes that go beyond the primary studies to answer the review’s specific question. That third stage is what separates thematic synthesis from a purely descriptive thematic summary — it is where new interpretation happens, in a more structured, transparent, team-friendly process than meta-ethnography’s translation-based approach.

Framework synthesis

Framework synthesis adapts the Framework Approach (originally a primary-analysis method from Ritchie and Spencer) to secondary synthesis: an existing conceptual or theoretical framework — often drawn from prior literature, a programme theory, or a policy model — is used a priori to index and chart findings from each included study into a matrix. It is the strongest choice when a defensible framework already exists and the review question is close to a policy or practice decision the framework was built to inform (a common “best-fit framework synthesis” variant starts from an existing framework and lets themes outside it emerge inductively, rather than forcing every finding into a pre-set box).

Meta-aggregation (JBI approach)

Meta-aggregation is the Joanna Briggs Institute’s method, run through JBI SUMARI software and widely used in nursing and allied-health guideline development. It is explicitly aggregative rather than interpretive, and follows three phases: extracting findings from each study and rating their credibility (JBI’s ConQual approach grades each finding unequivocal, credible, or unsupported, depending on how directly it is grounded in participant data); grouping findings into categories through constant comparison of similar meanings; and aggregating those categories into synthesised findings that are written to function as “lines of action” — recommendations usable directly in evidence-based practice. Because unsupported findings can be excluded at the credibility-rating stage, meta-aggregation trades some interpretive richness for a more transparent, gradable evidence chain than thematic synthesis or meta-ethnography.

Choosing among them

As a starting point: if a relevant theoretical or policy framework already exists and your question maps onto it, framework synthesis puts that structure to direct use. If no such framework exists and you want a widely applicable, moderately structured method a review team without deep interpretive training can execute consistently, thematic synthesis is the default choice for good reason — it is what most published QES in health and social policy actually use. If your synthesis needs to feed directly into a graded clinical or practice recommendation, meta-aggregation’s credibility-rating step gives that evidence chain built in. If the goal is genuinely new theory — translating studies into and against each other to build an interpretation none of the primary studies articulated — meta-ethnography remains the method built for that, at the cost of being harder to report transparently and more resistant to team-based, less experienced execution.

Reporting the synthesis: the ENTREQ statement

ENTREQ (Enhancing Transparency in Reporting the Synthesis of Qualitative Research) was developed by Tong, Flemming, McInnes, Oliver and Craig and published in BMC Medical Research Methodology in 2012, after being pilot-tested against 40 published qualitative syntheses. It is a reporting guideline, not a conduct manual: it does not tell you how to run a synthesis, only what a completed synthesis report needs to state explicitly so a reader can judge how the findings were produced. Its 21 items are organised into five domains:

• Introduction — item 1, stating the aim of the synthesis.
• Methods and methodology — item 2, naming and justifying the synthesis methodology used (this is the item that connects directly back to the choice above: thematic synthesis, framework synthesis, meta-aggregation, meta-ethnography, or another named approach, with a rationale for why it fits the question).
• Literature search and selection — items 3 through 9: approach to searching, inclusion criteria, data sources, the electronic search strategy, study screening methods, study characteristics, and study selection results.
• Appraisal — items 10 through 13: the rationale for appraising included studies, the appraisal items used, the appraisal process, and appraisal results (see CASRAI’s guides to general critical appraisal tools and the JBI critical appraisal checklists specifically).
• Synthesis of findings — items 14 through 21: data extraction, software used, number of reviewers involved, coding, how studies were compared, how themes or constructs were derived, use of participant quotations, and the synthesis output itself.

The authors are explicit that ENTREQ is “not an absolute, definitive framework” — the same spirit as eMERGe’s relationship to meta-ethnography: a reporting layer added on top of an existing method, not a replacement for it. ENTREQ complements, rather than duplicates, the search-and-selection reporting already required by PRISMA-style flow: use ENTREQ’s synthesis-specific items alongside your review’s PRISMA reporting rather than treating the two as competing checklists.

ENTREQ vs. COREQ and SRQR

It is easy to reach for the wrong checklist here. COREQ and SRQR report a single primary qualitative study — the interviews or focus groups a researcher actually ran. ENTREQ reports a synthesis of qualitative findings already published by other researchers. If your paper reports original interviews, use COREQ or SRQR; if it synthesises existing qualitative literature using one of the methods above, use ENTREQ.

Frequently asked questions

Is ENTREQ the same as PRISMA?

No. PRISMA reports the review process generally — search strategy, screening flow, study selection — and is not qualitative-synthesis-specific. ENTREQ adds items specific to qualitative synthesis (synthesis methodology, coding, derivation of themes, use of quotations) that a generic PRISMA report does not cover. Many qualitative evidence syntheses report against both.

Do I need ENTREQ if I already used eMERGe or a method-specific reporting guide?

If your synthesis used meta-ethnography specifically, eMERGe’s 19 criteria (organised under Noblit and Hare’s own seven phases) are the more detailed, method-specific reporting standard — see CASRAI’s meta-ethnography guide. ENTREQ remains the broader, method-agnostic option for thematic synthesis, framework synthesis, meta-aggregation, and other approaches that do not have their own dedicated reporting guideline.

What is the practical difference between thematic synthesis and meta-aggregation?

Thematic synthesis is interpretive: its final analytical-themes stage deliberately produces new interpretation that goes beyond what any single study said. Meta-aggregation is aggregative: it rates and combines existing findings into practice-ready statements, explicitly avoiding the kind of new theoretical claim thematic synthesis is built to generate. Choose based on whether your question needs a new interpretation or a synthesised, credibility-graded set of existing findings.

Where can I find worked examples of a synthesis methodology statement?

Published protocols and PROSPERO registrations for reviews using each method are the most reliable source of a real ENTREQ item 2 statement in context — searching a discipline-relevant database for “thematic synthesis protocol,” “framework synthesis protocol,” or “meta-aggregation JBI SUMARI” alongside your topic area will surface recent examples.