Master the PRISMA Flow Diagram in Just 5 Minutes

Table of Contents

1. Introduction
2. What is the PRISMA Flow Diagram?
3. The Purpose of the PRISMA Flow Diagram
4. Versions of the PRISMA Flow Diagram
5. Identification of Studies via Databases and Registers
   • Reporting the Number of Records Identified
   • Deduplication of Records
   • Removing Records for Other Reasons
6. Title and Abstract Screening
   • Eliminating Records based on Title and Abstract
   • Excluding Records using Automation Tools
7. Full Text Screening
   • Retrieving PDFs for Eligible Records
   • Excluding Records based on Eligibility Criteria
8. Other Searching Methods for Systematic Reviews
   • Hand Searching
   • Citation Searching
9. Additional Studies Found from Other Sources
10. Conclusion

What is the PRISMA Flow Diagram?

The PRISMA Flow Diagram is an essential tool used in systematic reviews to visually display the flow of information throughout the review process. It provides a step-by-step representation of how studies are identified, screened, and included or excluded from the review. The diagram follows the guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, which aims to improve the transparency and reporting of systematic reviews. By using the PRISMA Flow Diagram, researchers can ensure clarity and reproducibility in their systematic review methodology.

The Purpose of the PRISMA Flow Diagram

The main purpose of the PRISMA Flow Diagram is to provide a clear and transparent representation of the systematic review process. It allows readers to understand how studies were selected or excluded at each stage of the review, providing insights into the decision-making process. The diagram helps to address issues of bias and enhances the reproducibility of systematic reviews by promoting a standardized approach. Additionally, the PRISMA Flow Diagram enables researchers to identify potential gaps in the literature and highlight areas for further investigation.

Versions of the PRISMA Flow Diagram

The PRISMA Flow Diagram comes in several versions designed for different types of systematic reviews. There are two versions for new systematic reviews and two versions for updated systematic reviews. Furthermore, the diagram is divided based on the searching methods used. One version focuses on searching databases and registers only, while the other version includes searches of databases, registers, and other sources. Researchers should select the appropriate version that aligns with their specific review methodology.

Identification of Studies via Databases and Registers

The first step in the PRISMA Flow Diagram is the identification of studies via databases and registers. Researchers conduct searches in various databases and registers to gather relevant records for their systematic review. It is crucial to report the number of records identified from each database or register searched, rather than providing the total number across all databases. This detailed reporting allows for transparency and facilitates the reproduction of the review. Common databases used include Medline, Embase, Scopus, among others.

Reporting the Number of Records Identified

When reporting the number of records identified, researchers should include the total number of records found in each database or register. This information can be included in the narrative of the review or in the flow diagram itself. By reporting the numbers, readers gain insights into the search strategy and the sources from which relevant studies were identified.

Deduplication of Records

Deduplication is an important step in the systematic review process to ensure that each study is counted only once. Researchers often use automation tools or manual methods to identify and remove duplicate records. In the PRISMA Flow Diagram, the number of records removed through deduplication should be reported separately. This step helps to maintain the accuracy and integrity of the review.

Removing Records for Other Reasons

Apart from deduplication, there may be other reasons for removing records from the review. These reasons could include records that were not relevant to the research question or records that were not accessible. Researchers should keep track of the number of records removed for other reasons and report them in the flow diagram. This information provides transparency in the review process and ensures that the final included studies are valid and reliable.

Title and Abstract Screening

After the identification of studies, the next step in the PRISMA Flow Diagram is title and abstract screening. This stage involves evaluating the relevance of each study based on the information provided in the title and abstract. The aim is to reduce the number of records for in-depth evaluation in the full text screening stage.

Eliminating Records based on Title and Abstract

During title and abstract screening, researchers assess the suitability of each study based on predetermined inclusion and exclusion criteria. Studies that do not meet the criteria are excluded from further consideration. The PRISMA Flow Diagram displays the number of records that require full text screening after title and abstract screening.

Excluding Records using Automation Tools

Automation tools can be used during the title and abstract screening process to facilitate the efficient and systematic exclusion of irrelevant records. If automation tools were employed, it is important to indicate the number of records excluded by both human decision-making and the automation tools. This information helps to maintain transparency and allows for reproducibility of the review.

Full Text Screening

Once the title and abstract screening is completed, the next step in the PRISMA Flow Diagram is full text screening. This stage involves obtaining the full text of the selected studies and conducting a thorough evaluation to determine their eligibility for inclusion in the review.

Retrieving PDFs for Eligible Records

During full text screening, researchers retrieve the PDFs of the selected studies for a detailed assessment. In some cases, it may not be possible to locate or retrieve the full text of certain records. The PRISMA Flow Diagram includes a box to indicate the number of records that were not retrieved during this stage, ensuring transparency in the review process.

Excluding Records based on Eligibility Criteria

In full text screening, researchers apply predefined eligibility criteria to assess the suitability of each study for inclusion in the systematic review. The reasons for excluding a study should be documented, either in the flow diagram or in the narrative of the review. The number of records excluded for each reason is reported in the flow diagram, providing crucial information for transparency and reproducibility.

Other Searching Methods for Systematic Reviews

In addition to searching databases and registers, researchers conducting systematic reviews should consider other searching methods to ensure comprehensive coverage of relevant studies. These additional methods include hand searching and citation searching.

Hand Searching

Hand searching involves manually searching through reference lists of included studies, conference proceedings, and relevant journals or books. This method helps to identify studies that may not be indexed in electronic databases. The PRISMA Flow Diagram provides a section to report the number of potential websites or other sources that were hand searched, allowing researchers to demonstrate the breadth of their search strategy.

Citation Searching

Citation searching involves examining the references cited within the included studies to identify additional relevant records. By following citation trails, researchers can discover studies that may have been missed through other search methods. The PRISMA Flow Diagram includes a section to report the number of additional records that were identified through citation searching, ensuring transparency in the review process.

Additional Studies Found from Other Sources

In some cases, researchers may find additional studies beyond those identified through databases, registers, hand searching, or citation searching. These studies could be obtained from sources such as colleagues, experts in the field, or unpublished sources. Researchers should document the number of additional studies found and include this information in the flow diagram to provide a comprehensive overview of the search process.

Conclusion

The PRISMA Flow Diagram is a valuable tool for systematic reviewers to visually represent the identification, screening, and inclusion/exclusion process of studies in a clear and standardized manner. By following the guidelines and using the appropriate version of the diagram, researchers can ensure transparency, reproducibility, and reliability in their systematic reviews. The flow diagram should be included in the final publication of the review to enhance the understanding and trustworthiness of the review methodology.