Strata Academy

PRISMA 2020 Checklist & Flow Diagram (Step-by-Step)

Complete the 27-item PRISMA 2020 checklist and reconcilable flow diagram — plus PROSPERO tips and how PRISMA differs from AMSTAR 2

• PRISMA = reporting transparency; AMSTAR 2 = methodological conduct quality.
• The flow diagram must reconcile identification, screening, exclusion, and inclusion counts.
• Register on PROSPERO before screening — compare protocol to published methods.
• Full search strategies belong in supplements (PRISMA-S), not vague 'we searched PubMed'.
• Match risk-of-bias tools to each included study design in the methods section.

1. What is PRISMA 2020?

PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) is an evidence-based minimum set of items for reporting systematic reviews and meta-analyses. The 2020 update expanded guidance for new review types, search reporting, and synthesis without meta-analysis.

PRISMA is a reporting guideline – it asks whether authors transparently described what they did. It is not the same as assessing whether the review was conducted well (AMSTAR 2) or whether included studies are biased (ROB 2 / ROBINS-I applied per study).

Think of PRISMA as answering: 'Could another team reproduce the review from the published report?' AMSTAR 2 asks: 'Did they make methodological choices that threaten validity?'

Most UK medical schools expect PRISMA flow diagrams in intercalated systematic review dissertations. Journals increasingly reject reviews without reconcilable flow counts or registration numbers.

PRISMA 2020 explicitly addresses reviews that include randomised and non-randomised studies — report separate flows or clearly labelled synthesis pathways. Mixed-design reviews are common in public health and surgery evidence synthesis.

2. The PRISMA 2020 flow diagram

The flow diagram is the visual summary every systematic review reader expects. It tracks records identified, deduplicated, screened, excluded (with reasons), full-text assessed, studies included, and – where relevant – studies in qualitative and quantitative synthesis.

When appraising a review, check that exclusion counts reconcile. Large drops between screened and included without clear reasons are a reporting red flag even before you open AMSTAR 2.

PRISMA 2020 updated the flow to separate identification sources, distinguish reports from studies, and document reasons for exclusion at each stage. Older reviews using PRISMA 2009 diagrams are still common — note the version when appraising.

Automation tools (Covidence, Rayyan) export PRISMA-compatible counts — verify that exported numbers match the published diagram before submitting your own dissertation.

• Identification – databases searched, registers, other sources, total records
• Screening – records removed before screening, records screened, records excluded
• Eligibility – reports sought, not retrieved, assessed for eligibility, exclusion reasons
• Included – studies in review, studies in synthesis, optional breakdown by design

Tip: If the flow diagram is missing or does not match the text, note it as a major PRISMA deficiency before judging the science.

Tick the 27-item PRISMA checklist interactively, or upload a review PDF for PRISMA-aligned reporting feedback. Open PRISMA checklist tool · Appraise a review PDF

3. Key PRISMA 2020 checklist domains

The full checklist has 27 items across title, abstract, methods, results, discussion, and other information. For student appraisal, focus on the items that most often drive reproducibility and bias.

Items 4–8 cover eligibility, information sources, search strategy, selection process, and data collection — the backbone of AMSTAR 2 critical items too.

Items 11–15 cover synthesis methods, study-level risk of bias, and certainty of evidence (GRADE). A review can report GRADE in PRISMA terms yet fail AMSTAR 2 if ROB did not influence synthesis.

Item 24–27 cover registration, protocol access, funding, and conflicts of interest — essential for detecting selective reporting and sponsorship bias.

• Protocol and registration – Was the review registered (PROSPERO, OSF) before screening? Were protocol deviations explained?
• Eligibility criteria – Clear PICO/PEO elements for participants, interventions, comparators, outcomes, study designs.
• Information sources – Which databases, date limits, grey literature, reference checking?
• Search strategy – Reproducible full strategies for at least one major database (not just 'we searched PubMed').
• Study selection – How many reviewers screened? How were disagreements resolved?
• Data extraction – Piloted forms? Duplicate extraction?
• Risk of bias in studies – Which tool per design (ROB 2, ROBINS-I, etc.)? How used in synthesis?
• Synthesis methods – Narrative only, meta-analysis, heterogeneity, sensitivity analyses?
• Certainty of evidence – GRADE or equivalent when findings support recommendations?

4. PRISMA vs AMSTAR 2 vs ROBIS

Students often conflate three tools that serve different purposes in evidence synthesis.

A review can score well on PRISMA reporting but poorly on AMSTAR 2 if, for example, the list of excluded studies was not reported or risk of bias was not incorporated into synthesis — PRISMA Item 5 may be satisfied narratively while AMSTAR 2 Item 7 fails.

ROBIS adds a risk-of-bias lens on the review process itself — were study identification and synthesis phases conducted in ways that could distort the result?

• PRISMA 2020 – Reporting transparency (what authors say they did).
• AMSTAR 2 – Methodological quality of the review (16 items, confidence rating).
• ROBIS – Risk of bias in the systematic review process itself (protocol, study selection, synthesis).
• ROB 2 / ROBINS-I – Risk of bias in each included primary study.
• GRADE – Certainty of evidence in the body of findings.

Note: A review can score well on PRISMA reporting but poorly on AMSTAR 2 if, for example, the list of excluded studies was not reported or risk of bias was not incorporated into synthesis.

5. Worked example – reconciling the flow diagram

Pick a published systematic review and manually reconcile PRISMA flow counts against the methods text. Discrepancies between 'records screened' in text vs diagram are more common than students expect.

Practice on a Cochrane review first — they usually have detailed flows — then try a narrative review in a specialty journal with less rigorous reporting.

6. How to appraise a systematic review with PRISMA

Start with title and abstract – does the abstract follow PRISMA for Abstracts structure?

Open the methods and verify registration number and date. Compare registry protocol to published methods.

Request or locate supplementary search appendices. Without full strategies, the review is not reproducible.

Map each included study design to the correct risk-of-bias tool. Reviews that apply one checklist to every design are methodologically weak.

Read results and discussion for reporting bias, funding, and conflicts. PRISMA item 27 expects declaration of competing interests.

1. Check abstract structure against PRISMA for Abstracts.
2. Reconcile flow diagram counts with methods text.
3. Locate PROSPERO/OSF registration and compare to protocol.
4. Open search supplement — score PRISMA-S elements.
5. Note reporting gaps before AMSTAR 2 conduct scoring.

Tip: Use our interactive PRISMA checklist tool when completing dissertation appendices.

7. PRISMA extensions and review types

Not every synthesis is a pairwise meta-analysis of RCTs. PRISMA has extensions and related guidance for different review types.

Scoping reviews use PRISMA-ScR — a different extension with distinct checklist items. Do not apply the standard PRISMA 2020 checklist alone to scoping reviews without checking extension guidance.

Network meta-analyses require PRISMA-NMA extension items for presentation of multiple comparators and network geometry.

• PRISMA-P – Protocols (before results exist).
• PRISMA-S – Reporting literature searches in detail.
• PRISMA-NMA – Network meta-analyses.
• PRISMA-ScR – Scoping reviews (distinct from full systematic reviews).
• PRISMA-DTA – Diagnostic test accuracy reviews.

8. PROSPERO registration in practice

PROSPERO is the international prospective register of systematic reviews. Registration before screening is AMSTAR 2 item 2 and PRISMA best practice — it records your question, eligibility, and planned methods.

When appraising a review, compare the PROSPERO record date to screening start. Post-hoc registration or major unexplained deviations between protocol and published methods are red flags.

For student protocols, register on PROSPERO or OSF, paste the registration number in your dissertation methods, and cite it in the PRISMA methods section.

PROSPERO scope excludes some review types (e.g. certain rapid reviews) — OSF or institutional registries may be appropriate; document the choice in your methods.

• Record PICO, outcomes, and search sources at registration
• Note amendments with dates if eligibility changes after pilot screening
• Grey-literature-only or rapid reviews may use OSF when PROSPERO scope does not fit
• Compare published outcomes to registered outcomes — selective reporting signal

9. PRISMA-S for search reporting

PRISMA-S is an extension focused on how literature searches are reported — databases, platforms, date limits, filters, and full reproducible strategies. Weak search reporting is one of the fastest ways to fail AMSTAR 2 critical items.

Supervisors and peer reviewers increasingly expect at least one full database strategy (often PubMed or Embase) in a supplement, not a narrative summary alone.

When writing your own review, draft strategies with a librarian, store them in Covidence/Rayyan or Word appendices, and map each PRISMA-S element before submission.

UK university libraries often offer systematic review search support — use this early; retrofitting searches after screening is not credible.

• Name every database and register searched
• Report date limits and language restrictions
• Provide full strategies for peer review or supplementary files
• Document reference checking and citation searching

Tip: Pair PRISMA-S reporting with our PICO builder (/tools/pico-builder) so eligibility and search concepts stay aligned.

10. PRISMA for student dissertations

UK intercalated and MSc systematic review dissertations typically require a PRISMA 2020 flow diagram, completed checklist in an appendix, and PROSPERO registration number in the methods chapter. Marking rubrics often weight reproducibility as heavily as clinical interpretation.

Export screening counts from Covidence or Rayyan early and reconcile weekly — waiting until write-up to reconstruct numbers produces flow diagrams that do not match the screening log, a common cause of viva questions.

Include full search strategies as an appendix even if the word count is tight. PRISMA-S compliance protects you if examiners run AMSTAR 2 on your submission.

If you amend eligibility after pilot screening, update PROSPERO with dated amendment notes and explain the deviation in PRISMA methods. Undocumented post-hoc narrowing of inclusion criteria resembles selective inclusion.

Separate PRISMA flows for each synthesis if you run distinct meta-analyses (e.g. RCTs vs observational studies). A single combined flow obscures how many studies entered each synthesis pathway.

Word-count pressure: even if the main thesis chapter summarises search methods, appendices must contain full PRISMA-S strategies. Examiners often mark appendices separately from narrative chapters.

1. Register protocol before database search execution.
2. Save deduplication and screening logs with dates.
3. Build flow diagram incrementally during screening.
4. Complete PRISMA checklist before submission draft.
5. Ask supervisor to reconcile flow counts in penultimate draft.

12. Journal club checklist (PRISMA)

Project the flow diagram and reconcile one number aloud — records screened vs text in methods. Discrepancies are high-yield teaching moments.

Check PROSPERO registration date vs methods timeline. Post-hoc registration deserves explicit mention even if the science looks sound.

Ask whether full search strategies are in the supplement. If not, state the review is not reproducible before discussing results.

Map included study designs to ROB tools named in methods — flag single-checklist approaches for all designs.

• Reconcile flow counts live
• Registration date vs screening start
• Search reproducibility from supplement
• Design-appropriate ROB tools per study
• PRISMA reporting vs AMSTAR conduct kept separate

13. Common student errors

PRISMA mistakes in dissertations often cost marks despite strong clinical content. These are the patterns supervisors flag most often.

• Treating PRISMA as a quality score – it is a reporting checklist.
• Citing PRISMA in the methods but omitting the flow diagram in results.
• Assuming database search without Embase or CENTRAL is adequate for all clinical topics (depends on field – note limitation).
• Ignoring overlap when reviews include non-randomised and randomised studies without separate synthesis.
• Flow diagram counts that do not reconcile with text or Covidence exports.
• Using PRISMA 2020 checklist on a scoping review without PRISMA-ScR.

14. StrataResearch and systematic reviews

StrataResearch routes systematic review and meta-analysis manuscripts to AMSTAR 2, PRISMA 2020, ROBIS, and GRADE-aligned pathways – not to ROB 2 alone. Uploading a review PDF triggers study-type detection so you do not manually select the wrong framework.

Use our systematic review methodology guide for the full workflow from question to synthesis, then validate your own review report against PRISMA before submission.

Compare StrataResearch PRISMA-themed output to your manual checklist — gaps often appear in search reporting and exclusion documentation.

• PRISMA flow and checklist alignment on review uploads
• AMSTAR 2 and ROBIS on the same document
• Registration and protocol deviation prompts

Frequently asked questions

What is the PRISMA 2020 checklist?

PRISMA 2020 is a 27-item reporting checklist plus flow diagram for systematic reviews and meta-analyses. It documents search, screening, eligibility, and inclusion so another team could reproduce the review — it does not score methodological quality (use AMSTAR 2 for that).

How do I complete a PRISMA 2020 flow diagram?

Start with identification counts from each database and register, then add screening, eligibility (full-text excluded with reasons), and included studies. Numbers must reconcile across the diagram, methods text, and supplements — use our interactive flow tool or the official PRISMA template.

How many items are in the PRISMA 2020 checklist?

The PRISMA 2020 statement has 27 checklist items spanning title, abstract, methods, results, discussion, and other information (registration, funding, conflicts). Pair high-yield methods items with AMSTAR 2 when you are appraising a published review.

What is the difference between PRISMA 2020 and AMSTAR 2?

PRISMA 2020 assesses whether a systematic review is reported transparently (flow diagram, search strategy, exclusions). AMSTAR 2 assesses whether the review was conducted with sound methodology. Use both when appraising published systematic reviews.

Do I need PROSPERO registration for PRISMA 2020?

PRISMA 2020 expects you to report protocol registration (often PROSPERO) and explain deviations. Register before screening starts, then compare the published methods to the protocol when completing checklist items on registration and amendments.

Interactive walkthroughs and quizzes load when JavaScript is enabled — the checklist and tables above are fully readable without it.