A systematic review looks, from the outside, like a single coherent document with a tidy list of authors. From the inside it is a small project with a remarkable division of labour: a protocol to register, a search strategy to design and run across multiple databases, thousands of records to screen against eligibility criteria, full texts to retrieve and assess, data to extract twice over, risk-of-bias judgements to make, a synthesis or meta-analysis to compute, and a report to write to an exacting standard. Each of those tasks is a distinct skill, and each is usually done by a different person or pair of people. The conventional author byline flattens all of it. This article looks at how structured reporting through PRISMA and structured contributorship through the CRediT taxonomy together make the real shape of this work visible, and where the vocabulary for it sits in the credit extensions domain of the CASRAI Dictionary.
Why a review is hard to credit fairly
The difficulty is that the most laborious and methodologically critical parts of a review are precisely the ones that leave no trace in a traditional byline. Screening twenty thousand abstracts in duplicate is exacting, consequential work — get the eligibility judgements wrong and the whole review is compromised — yet it is invisible in author order. The same is true of designing a reproducible search, performing duplicate data extraction, or making risk-of-bias assessments. Meanwhile, the person who conceived the question and the person who drafted the manuscript are easy to recognise. A fair account of a review has to name the unglamorous, high-stakes tasks as clearly as the visible ones.
PRISMA: reporting the process transparently
The first half of the answer is methodological transparency. PRISMA — Preferred Reporting Items for Systematic Reviews and Meta-Analyses — is the reporting guideline that tells readers what a review actually did: how the search was constructed, how records moved from identification through screening to inclusion (the familiar flow diagram), how data were extracted, and how studies were appraised and synthesised. PRISMA does not assign credit, but it makes the work auditable. When a review reports its process to the PRISMA standard, the existence and scale of each task — the searching, the screening, the extraction, the appraisal — becomes explicit rather than implied. That visibility is the precondition for crediting it: you cannot recognise a contribution that the reporting has hidden.
CRediT: naming who did what
The second half is contributorship. The Contributor Roles Taxonomy provides a controlled vocabulary of contribution types that maps unusually well onto the anatomy of a review. The full set is set out in our overview of the CRediT roles, but several are worth singling out for evidence synthesis:
- Conceptualization — formulating the review question and eligibility criteria.
- Methodology — designing the search strategy and the synthesis approach, often the work of an information specialist.
- Investigation — running the searches, screening records and retrieving full texts.
- Data curation — managing the extracted data, de-duplication and the records that underpin the flow diagram.
- Formal analysis — the meta-analysis itself, including heterogeneity assessment and any sensitivity analyses.
- Writing – original draft and Writing – review & editing — producing and refining the manuscript.
Used together, these roles let a review record that the information specialist designed the search, that two named reviewers screened and extracted in duplicate, and that the statistician ran the synthesis — rather than leaving all of it to be guessed from author order. The wider CRediT taxonomy turns the division of labour into a machine-readable statement attached to the output.
The role information specialists deserve
One contribution that systematic reviews chronically under-credit is that of the information specialist or research librarian who designs and validates the search. A poorly constructed search undermines a review more surely than almost any other flaw, and a well-constructed one is a genuine methodological achievement. Recording this work explicitly under Methodology and Investigation — rather than relegating it to an acknowledgement — is one of the clearest practical gains from applying contributorship to evidence synthesis. It names a contribution that is both critical and routinely invisible.
Crediting duplicate work without double-counting
Reviews rely on tasks done independently by two people — duplicate screening, duplicate extraction — precisely to reduce error. Contributorship should reflect that both reviewers did the work, which CRediT handles naturally by allowing a role to be assigned to more than one contributor. The honest principle, as ever, is that a role records what a person actually did: both screeners earn the Investigation role because both genuinely screened, not as a courtesy. This is the same standard that applies across all contribution recording — credit follows real work, and is neither inflated for visibility nor withheld for convenience.
A consistent record across systems
Systematic reviews increasingly register protocols, deposit search strategies and data, and publish in journals that require both PRISMA reporting and a contributorship statement. For that ecosystem to work, the way a contribution is described has to mean the same thing wherever it appears. That consistency is what the CASRAI Dictionary exists to provide: a stable vocabulary so that a Methodology contribution declared in a protocol registry, a manuscript and an institutional record can be recognised as the same claim. Combined with PRISMA’s transparency about process, structured contribution makes the substantial, distributed work of evidence synthesis legible — crediting the screeners, extractors and search designers whose labour holds a review together, not only the names at the top of the list.