PRISMA 2020 Checklist: Complete Guide for Students & Researchers

TL;DR: The PRISMA 2020 checklist is a 27-item reporting guideline that ensures transparency, completeness, and reproducibility in systematic reviews and meta-analyses. It covers title, abstract, introduction, methods, results, discussion, and funding sections. Key updates from PRISMA 2009 include more inclusive wording, sub-items for complex topics, and a flexible flow diagram. For students, the checklist provides a step-by-step framework to structure high-quality reviews that meet journal standards and avoid common pitfalls like incomplete search reporting or bias assessment omissions.

What Is PRISMA 2020 and Why Does It Matter?

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, published simultaneously in five leading journals including the BMJ and Annals of Internal Medicine, replaces the 2009 version and reflects advances in review methodology over the past decade¹.

For students and early-career researchers, PRISMA 2020 matters because:

• Mandatory for publication: Most peer-reviewed journals in health sciences, education, and social sciences require PRISMA adherence.
• Ensures transparency: The checklist forces you to document every methodological decision, making your review reproducible.
• Improves quality: Following PRISMA reduces common errors like selective outcome reporting or inadequate search strategies.
• Facilitates peer review: Reviewers use the checklist to evaluate your manuscript; non-compliance often leads to desk rejection.

This guide walks you through all 27 PRISMA 2020 items, explains how to complete the flow diagram, highlights key changes from 2009, and identifies frequent student mistakes to avoid.

The PRISMA 2020 Checklist: All 27 Items Explained

The checklist is organized by manuscript section. Each item includes a heading, a concise statement, and detailed reporting recommendations in the expanded version². Below is a practical explanation tailored for students.

Section 1: Title & Abstract (Items 1–2)

Item 1: Title

Requirement: Identify the report as a systematic review.

What to include: The title must contain the phrase “systematic review” (or “systematic literature review”). If you conducted a meta-analysis, include that term. Example: “Effectiveness of Mindfulness-Based Interventions for Anxiety: A Systematic Review and Meta-Analysis.”

Common mistake: Using vague titles like “A Review of the Literature” that don’t signal systematic review methodology.

Item 2: Structured Summary (Abstract)

Requirement: Provide a structured abstract covering background, objectives, methods, results, and conclusions.

What to include:

• Background: Rationale and research question.
• Objectives: PICO/PECO question and primary outcomes.
• Methods: Databases searched, dates, number of reviewers, quality assessment tool, synthesis method.
• Results: Number of studies included, total participants, primary effect sizes with confidence intervals.
• Conclusions: Summary of findings and implications.
• Funding sources: Any grants or support.

Word limit: Many journals cap abstracts at 250–300 words; be concise but complete.

Section 2: Introduction (Items 3–4)

Item 3: Rationale

Requirement: Describe the rationale for the review in the context of existing knowledge.

What to include: Explain why this systematic review is needed. What gap in knowledge does it fill? Reference key studies and highlight inconsistencies or unanswered questions.

Item 4: Objectives

Requirement: Provide explicit, answerable research questions or hypotheses with defined PICO/PECO elements.

What to include:

• Population: Who or what you’re studying (e.g., adults with major depressive disorder).
• Intervention/Exposure: What treatment or exposure of interest (e.g., cognitive behavioral therapy).
• Comparison: Control or alternative intervention (e.g., placebo, usual care).
• Outcome: Primary outcomes (e.g., remission rates, symptom scores).

Example: “In adults with generalized anxiety disorder (P), does mindfulness-based stress reduction (I) compared to waitlist control (C) reduce anxiety symptoms (O) as measured by the GAD-7 scale?”

Section 3: Methods (Items 5–16)

This is the longest section and where students often lose points. Be meticulous.

Item 5: Protocol and Registration

Requirement: Indicate whether a protocol exists and provide access details (e.g., registration number, URL).

What to include: Many students skip registering a protocol, but it’s a hallmark of rigorous reviews. Register with PROSPERO (for health-related reviews) or publish a preprint. State the registration number and date.

Item 6: Eligibility Criteria

Requirement: Specify all eligibility criteria using PICOS elements and any additional criteria (e.g., study design, language, publication dates).

What to include: Clear inclusion/exclusion criteria:

• Study designs: RCTs only? Observational studies? Qualitative?
• Participants: Age range, condition, setting.
• Interventions: Specific therapies or exposures.
• Outcomes: Which outcomes are required? Minimum follow-up?
• Timeframe: Publication date range (e.g., 2010–2024).
• Language: English only or all languages?
• Publication status: Peer-reviewed journals only? Include grey literature?

Item 7: Information Sources

Requirement: Describe all information sources (databases, registers, websites, etc.) and any date restrictions.

What to include: List each database (e.g., PubMed, PsycINFO, CINAHL, Web of Science) and the date range searched. Also mention trial registers, conference abstracts, hand-searching key journals, and reference list scanning. Do not just say “multiple databases.”

Item 8: Search

Requirement: Present the full search strategies for all databases, including any filters used.

What to include: Appendix or supplementary file with the exact search strings for each database, including Boolean operators, MeSH terms, keywords, and limits. Example: “PubMed search: ((‘mindfulness'[MeSH Terms]) OR (‘mindfulness-based stress reduction’)) AND (‘anxiety disorders'[MeSH Terms]) AND (‘randomized controlled trial'[Publication Type]).”

Item 9: Selection Process

Requirement: State the process for selecting studies (number of reviewers, resolution of disagreements).

What to include: “Two independent reviewers screened titles and abstracts, removing duplicates. Full-text articles were assessed for eligibility by both reviewers independently. Disagreements were resolved by consensus or by a third reviewer.” Include the screening software used (e.g., Covidence, Rayyan).

Item 10: Data Collection Process

Requirement: Describe methods for data extraction and any processes for obtaining and confirming data from investigators.

What to include: Pre-piloted data extraction form? Two independent extractors? How were discrepancies resolved? Did you contact study authors for missing data? If so, how many responded?

Item 11: Data Items

Requirement: List and define all variables for which data were sought (e.g., PICOS items, funding sources).

What to include: Provide a table of extracted data fields: author, year, country, study design, sample size, participant characteristics, intervention details, outcomes, follow-up duration, main results, funding source, conflicts of interest.

Item 12: Study Risk of Bias Assessment

Requirement: Describe the tools used to assess risk of bias in individual studies.

What to include: Specify the tool per study design:

• RCTs: Cochrane Risk of Bias 2 (RoB 2) tool
• Non-randomized studies: ROBINS-I
• Cohort studies: Newcastle-Ottawa Scale (NOS)
• Qualitative studies: CASP Qualitative Checklist

Mention whether assessment was done by two independent reviewers and how disagreements were resolved.

Item 13: Effect Measures

Requirement: Specify the effect measures used in the synthesis (e.g., risk ratio, mean difference, odds ratio).

What to include: For each outcome, state the metric and whether you used fixed-effect or random-effects models. Justify model choice based on expected heterogeneity.

Item 14: Synthesis Methods

Requirement: Describe the synthesis methods, including how heterogeneity was assessed and explored.

What to include:

• Statistical software (e.g., RevMan, Comprehensive Meta-Analysis, R meta package).
• Heterogeneity assessment: I² statistic, χ² test (P-value threshold, usually P < 0.10).
• Subgroup analyses planned (if any).
• Sensitivity analyses (e.g., excluding high-risk-of-bias studies).
• Publication bias assessment: funnel plot, Egger’s test, or Trim-and-Fill method (note: funnel plots require ≥10 studies).

Item 15: Risk of Bias Across Studies

Requirement: Report any assessments of risk of bias across studies (e.g., outcome-level risk of bias, GRADE).

What to include: Use GRADE to rate certainty of evidence per outcome. Present a Summary of Findings table. Many student reviews omit this, but it’s increasingly expected.

Item 16: Additional Analyses

Requirement: Describe any additional analyses (e.g., subgroup, sensitivity, cumulative meta-analyses) and their rationale.

What to include: Distinguish between pre-specified and exploratory analyses. State whether adjustments for multiple testing were made.

Section 4: Results (Items 17–22)

Item 17: Study Selection

Requirement: Report the number of records identified in each database, the number after duplicates removed, the number screened, the number assessed for eligibility, and the number included in the review, with reasons for exclusions at each stage (ideally using a flow diagram).

What to include: The PRISMA flow diagram is mandatory. It has four boxes:

1. Identification: Records identified through database searching (n=) and additional sources (n=).
2. Screening: Duplicates removed (n=); records screened (n=); records excluded (n=).
3. Eligibility: Full-text articles assessed (n=); excluded with reasons (n=).
4. Included: Studies included in qualitative synthesis (n=); studies included in quantitative synthesis (meta-analysis) (n=).

Common mistake: Omitting the number of records excluded at full-text stage and their reasons. Provide a table: “Excluded at full text (n=52): 18 wrong population, 15 wrong intervention, 10 wrong outcome, 9 duplicate publication.”

Item 18: Study Characteristics

Requirement: Present characteristics of the included studies (e.g., study design, settings, participants, interventions, outcomes).

What to include: A descriptive table summarizing:

• Author, year, country
• Study design (RCT, cohort, etc.)
• Sample size per group
• Participant demographics (age, gender, condition severity)
• Intervention details (duration, frequency, provider)
• Comparator(s)
• Outcomes measured
• Follow-up timepoints

Item 19: Risk of Bias Within Studies

Requirement: Present data on risk of bias for each included study and summarize across studies.

What to include: Use traffic-light plots (green = low risk, yellow = some concerns, red = high risk) for each domain of the RoB 2 or ROBINS-I tool. Show a summary table or graph indicating the proportion of studies with low/moderate/high risk per domain. This transparency allows readers to judge the certainty of evidence.

Item 20: Results of Individual Studies

Requirement: For all outcomes, present results for each study (e.g., effect estimates, confidence intervals).

What to include: Usually in a forest plot (meta-analysis) or a standalone table. For each study, report:

• Effect size (e.g., mean difference, standardized mean difference, odds ratio, risk ratio)
• 95% confidence interval
• Number of participants (treatment and control)
• Weight in meta-analysis

Item 21: Results of Syntheses

Requirement: Present results of all quantitative syntheses (meta-analyses) and summarize the evidence supporting each finding.

What to include:

• Forest plot showing individual study effects and pooled effect with CI.
• I² statistic and P-value for heterogeneity.
• Direction and magnitude of effect with clinical interpretation.
• If no meta-analysis due to heterogeneity, present results narratively with effect sizes per study.

Item 22: Reporting Bias Assessment

Requirement: Present results of any assessment of reporting bias (e.g., funnel plots, Egger’s test).

What to include: Funnel plot (scatter of effect size vs standard error) should be provided. Asymmetry suggests publication bias. Report Egger’s test P-value if ≥10 studies. Note that funnel plots are unreliable with <10 studies.

Section 5: Discussion (Items 23–25)

Item 23: Summary of Evidence

Requirement: Summarize the main findings, including the strength and quality of evidence.

What to include: Restate the primary answer to your research question in plain language. How many studies included? Total participants? Overall effect size and its magnitude (small/medium/large)? How consistent were findings across studies? Compare with prior reviews if applicable.

Item 24: Limitations

Requirement: Discuss limitations at both review level and study level.

What to include:

• Review limitations: Language restriction? Exclusion of grey literature? Potential publication bias? Limited number of studies?
• Study limitations: Risk of bias in included studies (e.g., inadequate blinding, small sample sizes, short follow-up).
• Certainty of evidence: Reference the GRADE assessment if done.

Item 25: Conclusions

Requirement: Provide a general interpretation of the results in the context of existing knowledge and implications for practice, policy, and future research.

What to include: What do the findings mean for clinicians, educators, or policymakers? What are the practical implications? What research gaps remain? Avoid overstating; conclusions must be supported by your results.

Section 6: Funding & Other (Items 26–27)

Item 26: Funding

Requirement: Describe sources of funding and the role of funders for the systematic review.

What to include: Grant numbers, institutions, or “self-funded” if applicable. State whether funders had any role in study design, data collection, analysis, or manuscript preparation. If no funding, write “This review received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.”

Item 27: Other

Requirement: Register other relevant information, such as protocol amendments, availability of data, or conflicts of interest.

What to include: Conflicts of interest statements for all authors. Availability of data and code (e.g., “All extracted data are available at [repository URL]”).

PRISMA 2020 vs PRISMA 2009: Key Changes

The update from PRISMA 2009 to PRISMA 2020 reflects methodological advancements and broader inclusivity³. Key differences include:

1. More Inclusive Wording

The 2020 statement intentionally uses inclusive language to accommodate diverse review types beyond intervention reviews (which were the original focus). It now explicitly applies to:

• Qualitative systematic reviews
• Mixed-methods reviews
• Scoping reviews (though a separate PRISMA-ScR exists)
• Living systematic reviews
• Reviews of economic evaluations

2. Expanded Checklist with Sub-Items

Several items now include sub-items to provide more granular guidance. For example, Item 8 (Search) now requires reporting of:

• All electronic search strategies (full text for at least one database)
• Dates when searches were last run
• Any additional sources (e.g., trial registries, reference lists)

3. Flexible Flow Diagram

The PRISMA 2020 flow diagram is more adaptable than the 2009 version⁴. Optional fields allow reporting of:

• Records identified through additional methods (e.g., handsearching, contacting experts)
• Reports needed but not obtained
• Reasons for exclusion at full-text stage (recommended but not mandatory)

4. Emphasis on Protocol Registration

PRISMA 2020 strengthens the expectation that systematic reviews should have a pre-published or registered protocol to prevent selective reporting. Item 5 now explicitly asks for registration details.

5. Greater Attention to Risk of Bias

Items 12 and 15 now more clearly distinguish between risk-of-bias assessment within individual studies and across the body of evidence (e.g., using GRADE). The importance of evaluating certainty is emphasized.

Completing the PRISMA 2020 Flow Diagram

The flow diagram visually maps the study selection process, showing how many records progressed through each stage and why records were excluded. It consists of four boxes⁵:

1. Identification: Total records identified through database searching (report separately for each database) and additional sources (n=).
2. Screening: After deduplication, how many titles/abstracts were screened? How many were excluded and why (usually “not relevant”)?
3. Eligibility: How many full-text articles were assessed? How many were excluded with specific reasons (e.g., wrong study design, no comparison group, wrong outcome)?
4. Included: Final number of studies included in qualitative synthesis and, if applicable, quantitative synthesis (meta-analysis).

Practical tip: Use screening software like Covidence or Rayyan to track decisions and automatically generate PRISMA numbers. Many journals now request the flow diagram as a separate figure (usually Figure 1).

Common PRISMA Mistakes Students Make

Based on peer-review experience and reporting studies⁶, here are frequent errors to avoid:

1. Incomplete Search Strategy Reporting

Many students write: “We searched PubMed, PsycINFO, and Google Scholar.” PRISMA requires the full search strings for every database, ideally in an appendix. Without this, your review is not reproducible and may be rejected.

2. Vague Eligibility Criteria

“We included studies on anxiety” is insufficient. Be precise: population characteristics, intervention types, outcomes, study designs, dates, languages, and publication status.

3. Missing or Incorrect Flow Diagram

Submitting a diagram with only the final number of studies, omitting exclusions with reasons, violates PRISMA 2020. You must show the numbers at each stage and why full-texts were excluded (provide a table if space is limited).

4. Inadequate Risk of Bias Assessment

Simply stating “two reviewers assessed quality” is not enough. Report which tool was used, how disagreements were resolved, and present a summary table or plot showing risk of bias per study domain.

5. Unclear Statistical Synthesis

Failing to report the effect measure, model (fixed vs random), heterogeneity metrics (I², P-value), or software used makes the synthesis impossible to evaluate. Even if a meta-analysis wasn’t possible due to heterogeneity, explain why and describe the narrative synthesis approach.

6. Omitting Protocol Registration

While some student reviews still get published without a registered protocol, the expectation is rising. Registering your protocol (e.g., with PROSPERO) demonstrates methodological rigor and prevents outcome reporting bias.

7. Ignoring Publication Bias

If you include ≥10 studies in a meta-analysis, you must assess publication bias using funnel plots and statistical tests (Egger’s). Failing to do so is a major gap.

8. Misrepresenting Certainty of Evidence

Overstating conclusions without acknowledging study limitations or low-quality evidence is a red flag for reviewers. Use GRADE or at least discuss the strength of evidence.

PRISMA 2020 for Different Review Types

The main PRISMA 2020 statement targets systematic reviews of interventions, but adaptations exist⁷:

• PRISMA-ScR: For scoping reviews (broader mapping exercises). Uses a 22-item checklist.
• PRISMA for Abstracts: A shorter checklist for conference abstracts.
• PRISMA-NMA: For network meta-analyses.
• PRISMA-P: For protocols.

Students should select the appropriate extension depending on their review type. For most graduate theses, the main PRISMA 2020 checklist (for systematic reviews) or PRISMA-ScR will apply.

Practical Checklist for Students: Getting PRISMA Right

Before submitting your systematic review, run through this sanity check:

• Title includes “systematic review”?
• Abstract structured with background, objectives, methods, results, conclusions?
• Clear PICOS question stated in introduction?
• Protocol registered? (Provide registration number)
• Eligibility criteria specified in detail?
• Full search strategies for all databases included?
• Screening process described (two reviewers, conflict resolution)?
• Data extraction method described (piloted form, two reviewers)?
• Risk of bias tool named and applied (with summary table/plot)?
• Effect measures and synthesis model clearly stated?
• GRADE or other certainty assessment included?
• PRISMA flow diagram present and filled correctly?
• Results table shows individual study effect sizes?
• Forest plot provided (if meta-analysis done)?
• Funnel plot and publication bias test (if ≥10 studies)?
• Discussion covers limitations of included studies and review?
• Conclusions aligned with results and strength of evidence?
• Funding and conflicts of interest disclosed?
• All co-authors’ contributions declared?

Frequently Asked Questions (FAQ)

Can I use PRISMA for a literature review that is not systematic?

No. PRISMA is specifically for systematic reviews that follow a pre-registered protocol, comprehensive search strategy, and explicit inclusion criteria. Traditional narrative literature reviews do not require PRISMA.

What if my meta-analysis includes fewer than 10 studies?

You can still conduct a meta-analysis, but you should not rely heavily on funnel plots for publication bias assessment (it’s underpowered). Acknowledge this limitation. However, you must still report the effect estimate and heterogeneity.

Is PRISMA mandatory for all journals?

Most reputable journals in health sciences, education, and social sciences require PRISMA adherence for systematic review submissions. Check the journal’s author guidelines. Even if not mandatory, following PRISMA increases your chances of acceptance.

Where can I find the official PRISMA 2020 documents?

Visit the PRISMA website to download the checklist (PDF/Word), expanded checklist, flow diagram templates, and the explanation and elaboration paper⁸.

Conclusion: PRISMA 2020 as Your Roadmap to Rigorous Reviews

The PRISMA 2020 checklist is more than a bureaucratic hurdle—it’s a blueprint for producing transparent, reproducible, and high-quality systematic reviews. By systematically addressing each item, students can avoid common pitfalls and produce work that meets the highest methodological standards. Remember: good reporting is not about perfection; it’s about providing enough detail for others to understand, evaluate, and replicate your work.

If you need help ensuring your systematic review or meta-analysis complies with PRISMA 2020, our academic editing services include expert review of methodology, reporting completeness, and statistical interpretation by experienced researchers.

Related Guides

For further reading on research methodology and academic writing:

• How to Write a Systematic Literature Review: Student Edition (covers the broader process from protocol to writing)
• Annotated Bibliography Templates 2026 (source evaluation and synthesis)
• How to Write an Empirical Research Paper (research reporting fundamentals)
• Lab Report vs Research Paper: Key Differences (choosing the right format)
• The Complete Peer Review Process Guide for Students (understanding journal expectations)

References

1. Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. doi:10.1136/bmj.n71. https://pubmed.ncbi.nlm.nih.gov/33782057/
2. Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews. BMJ. 2021;372:n160. doi:10.1136/bmj.n160. https://pubmed.ncbi.nlm.nih.gov/33782058/
3. DistillerSR. PRISMA 2009 Versus PRISMA 2020. https://www.distillersr.com/resources/systematic-literature-reviews/prisma-2009-versus-2020
4. PRISMA Statement. PRISMA 2020 flow diagram.
5. University of North Carolina Library. Creating a PRISMA flow diagram: PRISMA 2020. https://guides.lib.unc.edu/prisma
6. Amiri F, Khankeh H, Ansari S. Addressing of PRISMA Checklist for Reporting Systematic Reviews. Health Promot Perspect. 2023;13:97–97. doi:10.34172/hpp.2023.12. https://doi.org/10.34172/hpp.2023.12
7. PRISMA Statement. Extensions.
8. PRISMA Statement. PRISMA 2020 checklist.