PRISMA Flow Diagram Template for Systematic Reviews
By Dr. Zubair Khalid, DVM, MS, PhD ·
Quick Answer
- Use the PRISMA 2020 flow diagram template to report the number of records identified, screened, sought, assessed, and included in a systematic review.
- Count each record once at each stage and report reasons for exclusion at the eligibility phase to make the review reproducible.
- The template is a reporting structure, not a study design, and it cannot fix a search strategy that was incomplete from the start.
What the PRISMA Flow Diagram Is and Why It Matters
The PRISMA flow diagram is a standardized visual summary of how records move through a systematic review. It shows the number of records identified from databases and other sources, the number removed as duplicates, the number screened by title and abstract, the number sought for full-text retrieval, the number assessed for eligibility, and the final number of studies included in the review.
Systematic reviews are used across biomedical and life-science fields to answer focused questions with a reproducible method. The flow diagram gives readers and reviewers a transparent account of the literature search and selection process. Without this transparency, a reader cannot tell whether the review team searched broadly enough, applied consistent inclusion criteria, or excluded studies for defensible reasons.
The PRISMA statement is a reporting guideline, not a conduct guideline. It tells authors what to report, not how to perform the review. The flow diagram is one component of the PRISMA 2020 checklist, which also covers title, abstract, introduction, methods, results, discussion, and funding information. The EQUATOR Network maintains a searchable library of reporting guidelines and recommends that authors select the appropriate guideline before starting their study and cite it in the manuscript.
For researchers preparing grant applications, the National Institutes of Health expects applications to describe the scientific premise, rigor, and transparency of the proposed work. A systematic review that will be part of a grant proposal should include a clear plan for the search and screening process, and the PRISMA flow diagram is the standard way to report the results of that process.
At a Glance: PRISMA Flow Diagram Structure
| Stage | What You Count | Common Source of Error |
|---|---|---|
| Identification | Records from databases, registers, and other sources | Forgetting to report records from registers separately |
| Screening | Records after duplicate removal, then records screened | Counting duplicates inconsistently across sources |
| Eligibility | Full-text reports sought and assessed | Not reporting reasons for exclusion at full-text stage |
| Included | Studies and reports included in synthesis | Confusing number of reports with number of studies |
Core Principles of the PRISMA Flow Diagram
Report the Flow of Records, beyond Studies
The flow diagram tracks records and reports, also final studies. A record is a single entry from a database or register. A report is a document that may contain one or more studies. A single study may be reported in multiple documents, such as a journal article, a conference abstract, and a clinical trial registry entry. The PRISMA 2020 flow diagram distinguishes between these levels so that readers can see the full path from search results to included studies.
Use the Four-Phase Structure
The PRISMA 2020 flow diagram has four phases: identification, screening, eligibility, and included. Each phase answers a specific question:
- Identification: How many records were found from each source?
- Screening: How many records were screened after duplicates were removed, and how many were excluded?
- Eligibility: How many reports were sought for retrieval, how many were assessed, and how many were excluded with reasons?
- Included: How many studies and reports were included in the review?
The four-phase structure is the same whether you are conducting a review of randomized trials, observational studies, diagnostic accuracy studies, or qualitative research. The template does not change based on study design, but the inclusion criteria and the reasons for exclusion will differ.
Report Numbers That Add Up
The numbers in the flow diagram must be internally consistent. The number of records screened must equal the number of records identified minus the number of duplicates removed. The number of reports assessed for eligibility must equal the number of reports sought for retrieval minus the number not retrieved. The number of studies included must equal the number of reports assessed minus the number excluded with reasons.
A common error is to report a number at one stage that does not match the numbers at adjacent stages. Reviewers and journal editors will check these arithmetic relationships, and an inconsistent flow diagram undermines confidence in the entire review.
How to Build Your PRISMA Flow Diagram
Step 1: Choose the Correct Template Version
The PRISMA 2020 flow diagram is the current version. It replaced the earlier PRISMA 2009 flow diagram. The 2020 version adds a separate box for records identified from registers and allows authors to report the number of records identified from each source separately.
Download the template from the PRISMA website or use the version provided by your target journal. Some journals provide their own templates or require a specific format. Check the journal's author instructions before you begin.
Step 2: Collect the Numbers You Need
Before you can fill in the flow diagram, you need to collect the following numbers from your review records:
- Number of records identified from each database
- Number of records identified from registers
- Number of records identified from other sources, such as citation searching or contact with authors
- Number of duplicate records removed
- Number of records screened by title and abstract
- Number of records excluded at title and abstract screening
- Number of reports sought for retrieval
- Number of reports not retrieved
- Number of reports assessed for full-text eligibility
- Number of reports excluded at full-text stage, with reasons
- Number of studies included in the review
- Number of reports of included studies
Keep a screening log from the start of the review. A simple spreadsheet with columns for record ID, source, screening decision, and exclusion reason will give you all the numbers you need when you are ready to build the flow diagram.
Step 3: Fill In the Identification Phase
In the identification phase, report the number of records identified from each database and register. The PRISMA 2020 template has separate boxes for databases and registers. If you searched five databases, list each database and the number of records retrieved from each. If you searched a clinical trial register, report those records separately.
Also report records identified from other sources, such as citation searching, reference list screening, or contact with study authors. These records are often missed in the identification phase, which leads to an incomplete flow diagram.
Step 4: Fill In the Screening Phase
The screening phase starts with the total number of records after duplicates are removed. Report the number of duplicates removed in the box provided. Then report the number of records screened by title and abstract and the number excluded at this stage.
You do not need to report reasons for exclusion at the title and abstract screening stage. The PRISMA 2020 guidance recognizes that reviewers often exclude large numbers of records at this stage for broad reasons, such as not addressing the research question or not meeting the study design criteria. Reasons for exclusion are required at the full-text stage.
Step 5: Fill In the Eligibility Phase
The eligibility phase tracks reports, not records. Report the number of reports sought for retrieval and the number not retrieved. Then report the number of reports assessed for eligibility and the number excluded, with reasons.
The PRISMA 2020 template includes a box for reporting the number of reports excluded and a separate space to list the reasons. Common reasons include wrong population, wrong intervention, wrong comparator, wrong outcome, wrong study design, duplicate publication, or insufficient data. List each reason and the number of reports excluded for that reason.
Step 6: Fill In the Included Phase
The included phase reports the number of studies included in the review and the number of reports of those studies. A study may have multiple reports, such as a primary article and a follow-up analysis. Report both numbers so that readers can see the relationship between studies and reports.
If your review includes a meta-analysis, report the number of studies included in the meta-analysis separately from the number included in the qualitative synthesis. The PRISMA 2020 template has a box for this distinction.
Step 7: Check the Arithmetic
Before you submit your manuscript, check that every number in the flow diagram is consistent with the numbers at adjacent stages. Use the following checks:
- Records screened = Records identified minus duplicates removed
- Records excluded = Records screened minus records assessed for eligibility
- Reports sought = Records assessed for eligibility
- Reports assessed = Reports sought minus reports not retrieved
- Studies included = Reports assessed minus reports excluded with reasons
If any of these relationships do not hold, trace the error back to your screening log and correct it.
Practical Implementation Steps
Set Up Your Screening Log Before You Search
Create a screening log before you run your first database search. The log should include columns for record ID, source database, title, authors, year, screening decision, and exclusion reason. Use a unique identifier for each record so that you can track duplicates across databases.
A spreadsheet program is sufficient for most reviews. For larger reviews with thousands of records, consider using a systematic review software tool that can import records from databases, remove duplicates, and track screening decisions.
Use a Two-Person Screening Process
The PRISMA flow diagram reports the results of screening, but it does not tell readers how screening was conducted. For a rigorous review, have two reviewers screen records independently at the title and abstract stage and at the full-text stage. Resolve disagreements by discussion or by a third reviewer.
The National Library of Medicine's Research Methods Resources provides guidance on systematic review methods, including screening and data extraction. Consult these resources when you are designing your screening process.
Document Exclusion Reasons at Full Text
The full-text stage is where you must report reasons for exclusion. Keep a list of exclusion reasons and apply them consistently. Common reasons include:
- Not a study (for example, an editorial or commentary)
- Wrong population
- Wrong intervention or exposure
- Wrong comparator
- Wrong outcome
- Wrong study design
- Duplicate publication
- Insufficient data
- Full text not available
Assign each excluded report to one reason. If a report could be excluded for multiple reasons, choose the primary reason and record it consistently.
Update the Flow Diagram After Peer Review
Peer reviewers may ask you to clarify your search or screening process. If you make changes to your search strategy or inclusion criteria during revision, update the flow diagram to match. Do not submit a flow diagram that does not match the methods described in your manuscript.
Records and Measurements
What to Record During the Search
Record the date of each search, the database searched, the search strategy used, and the number of records retrieved. This information is needed for the flow diagram and for the supplementary materials that many journals require.
The National Institutes of Health Data Management and Sharing Policy expects researchers to plan for the management and sharing of data generated by their projects. For a systematic review, the search strategies, screening decisions, and data extraction forms are part of the research data and should be preserved and shared where appropriate.
What to Record During Screening
Record the screening decision for each record and the reviewer who made the decision. If you use a two-person screening process, record both decisions and the resolution of disagreements. This information is useful for calculating inter-reviewer agreement and for responding to peer review comments.
What to Record During Eligibility Assessment
Record the reason for exclusion for each report assessed at the full-text stage. Keep this list in your screening log so that you can report the numbers accurately in the flow diagram.
Common Failure Patterns
Failure to Report Registers Separately
The PRISMA 2020 flow diagram requires separate reporting of records from databases and records from registers. Many authors combine these numbers, which makes it impossible for readers to see how many records came from each source. If you searched a clinical trial register, report those records in the register box.
Failure to Report Other Sources
Records identified from citation searching, reference list screening, or contact with authors are often omitted from the flow diagram. These records are part of the identification phase and must be reported. If you do not report them, your flow diagram will undercount the total number of records identified.
Inconsistent Numbers Between Stages
The most common failure is arithmetic inconsistency between stages. For example, the number of records screened may not equal the number identified minus duplicates, or the number of reports assessed may not equal the number sought minus not retrieved. Reviewers and editors check these relationships, and an inconsistent flow diagram is a common reason for revision requests.
Confusing Reports With Studies
A study may have multiple reports, and a single report may describe multiple studies. The PRISMA 2020 flow diagram distinguishes between reports and studies. If you report the number of reports included but not the number of studies, or vice versa, readers cannot tell how many distinct studies your review covers.
Omitting Exclusion Reasons
The PRISMA 2020 template requires reasons for exclusion at the full-text stage. Some authors report only the number excluded without listing reasons. This omission makes it impossible for readers to assess whether the exclusion criteria were applied appropriately.
Limitations and Professional Escalation Criteria
The Flow Diagram Does Not Validate Your Search
The PRISMA flow diagram is a reporting tool, not a quality assessment tool. A flow diagram can be perfectly filled in and still describe a poorly conducted review. The flow diagram cannot tell readers whether your search strategy was comprehensive, whether your inclusion criteria were appropriate, or whether your screening was reliable.
When to Seek Professional Help
If you are conducting a systematic review for a regulatory submission, a clinical guideline, or a grant application, consider consulting a librarian or information specialist with systematic review expertise. A librarian can help you design and execute a comprehensive search strategy, which is the foundation of the flow diagram.
If your review is part of a graduate thesis or dissertation, consult your advisor or committee before you begin. They can help you select the appropriate reporting guideline and review the flow diagram before you submit.
When to Escalate to an Ethics or Compliance Office
The Committee on Publication Ethics Core Practices address authorship, peer review, data, conflicts of interest, and misconduct. If you suspect that a colleague or collaborator has fabricated search results, falsified screening decisions, or plagiarized a published flow diagram, escalate the concern to your institution's research integrity office.
If your review is funded by the National Institutes of Health, your institution's sponsored projects office can help you understand the data management and sharing requirements that apply to your award. The NIH Data Management and Sharing Policy requires researchers to submit a data management and sharing plan with their application and to comply with the plan during the award period.
Welfare and Safety Context
Research Integrity and Publication Ethics
The PRISMA flow diagram is part of the broader framework of research integrity and publication ethics. The Committee on Publication Ethics Core Practices state that authors should accurately report their research and that journals should investigate allegations of misconduct. A flow diagram that misrepresents the number of records identified or excluded is a form of inaccurate reporting.
Data Management and Sharing
The National Institutes of Health Data Management and Sharing Policy applies to NIH-funded research, including systematic reviews. The policy expects researchers to preserve and share the data that support their findings. For a systematic review, this includes the search strategies, screening decisions, and data extraction forms. Plan for data management before you begin the review, and preserve your screening log so that you can share it if required.
Researcher Identity and Attribution
The ORCID for Researchers resource explains how researchers can maintain a persistent digital identifier that links their publications and research activities. If you are conducting a systematic review as part of a collaborative team, ensure that all authors have ORCID identifiers and that the final publication credits all contributors appropriately.
Frequently Asked Questions
What is the difference between PRISMA 2020 and PRISMA 2009?
The PRISMA 2020 flow diagram adds a separate box for records identified from registers and allows authors to report records from each source separately. The 2009 version combined database and register records into a single box. The 2020 version also clarifies the distinction between reports and studies in the included phase.
How many records should I expect to exclude at the title and abstract screening stage?
There is no standard number or percentage. The number depends on the breadth of your search strategy and the specificity of your research question. A broad search for a narrow question may exclude 90 percent or more of records at title and abstract screening. Report the actual number from your review, not an expected or target number.
Do I need to report reasons for exclusion at the title and abstract stage?
No. The PRISMA 2020 guidance requires reasons for exclusion at the full-text eligibility stage only. At the title and abstract stage, you report the number of records excluded without listing reasons.
Can I use the PRISMA flow diagram for a scoping review or a narrative review?
The PRISMA flow diagram was designed for systematic reviews, but it is often adapted for scoping reviews and other evidence synthesis methods. If you use the flow diagram for a different type of review, check the reporting guideline for that review type. The EQUATOR Network maintains a library of reporting guidelines for many study types.
What should I do if a full-text report cannot be retrieved?
Report the number of reports not retrieved in the eligibility phase of the flow diagram. Do not exclude these reports from the diagram. If you requested a report from the authors or through interlibrary loan and could not obtain it, record that in your screening log and report the number in the flow diagram.
How do I count a study that is reported in multiple publications?
Count the study once in the included studies box and count each publication as a separate report. The PRISMA 2020 flow diagram has separate boxes for studies and reports so that you can report both numbers.
Where can I find the official PRISMA 2020 flow diagram template?
The PRISMA statement website provides the official templates and checklists. Many journals also provide templates in their author instructions. The EQUATOR Network provides access to the PRISMA 2020 guideline and links to the full statement.
Should I include the PRISMA flow diagram in the main manuscript or as a supplementary file?
Most journals expect the flow diagram in the main manuscript, usually in the results section. Check the author instructions for your target journal. Some journals require the flow diagram as a separate file or in a specific format.
Using the Evidence
| Source | Best use in this topic | Important limitation |
|---|---|---|
| Research Methods Resources | official guidance | Check the linked page for current local requirements |
| EQUATOR Network | official guidance | Check the linked page for current local requirements |
| Core Practices | official guidance | Check the linked page for current local requirements |
Related Articles
- Data Management Plan Template: A Practical Guide for Researchers
- Data Management Platform: What It Is and How to Choose One
- Bioinformatics Internships: How to Land One and Make the Most of It
- The Role of the Research Ethics Committee: What Researchers Need to Know
- Scientific Literature Review Format: A Reproducible Structure for Researchers
References and Further Reading
- Research Methods Resources. National Library of Medicine.
- EQUATOR Network. EQUATOR Network.
- Core Practices. Committee on Publication Ethics.
- NIH Grants and Funding. National Institutes of Health.
- ORCID for Researchers. ORCID.
- Data Management and Sharing Policy. National Institutes of Health.
- NCBI Literature Resources. National Center for Biotechnology Information.
- PubMed. National Library of Medicine.
This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.