PRISMA for systematic reviews and meta-analyses

By Avishek Majumder on March 19, 2019
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The PRISMA framework or Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), is a set of guidelines or steps developed by Moher, (2013). These steps are useful for systematic literature reviews, critical literature analyses and meta-analyses. The PRISMA tool or framework uses a set of methods to systematically search papers and literature for review based studies. In addition, PRISMA is also based on the formulated inclusion and exclusion criteria in any type of study that systematically assesses the quality of chosen papers and either includes for the study or excludes for the study.

PRISMA is used mostly in medical and pharmaceutical researches, however, in recent years the use of PRISMA is also done in management studies and other non-medical studies.

The PRISMA concept

There are a few important things to note while formulating PRISMA. The PRISMA is based on the 27-item quality checklist broadly divided into:

  • Title,
  • Abstract,
  • Introduction,
  • Methods,
  • Results,
  • Discussion and,
  • Funds (Moher, 2013).

It is not mandatory to use all the checklist items; however, the inclusion and exclusion criteria are mostly based on the checklist items. The main role of the PRISMA checklist is to identify the quality of the papers identified using search strategies and databases. In addition, the flow chart of PRISMA is based on 4 stages:

  1. identification,
  2. screening,
  3. eligibility and,
  4. included.

The PRISMA checklist

Section/topic Sl. No. Checklist item Level of importance
Title 1 Identify the report as a systematic review, meta-analysis, or both, or the type of paper and the title scope. High
Abstract 2 Clarity of the study with; background, aim, methods used, findings, conclusion and other relevant information. High
Introduction 3 Must have a rationale.High
  4 Must mention the objectives of the studyHigh
Methods 5 Protocol registration.Low
  6 Eligibility criteria mentioned.Moderate
  7 Information sources or the data collection sources.High
  8 Search strategies or the research paradigm/philosophy.Moderate
  9 Study selection or the research approach.Moderate
  10 Data collection process or the sample size.High
  11 Data items.Moderate
  12 Risk of bias in individual studies. Low
  13 Summary measures or the tools of analysis High
  14 Synthesis of results or the methods of analysis High
  15 Risk of bias across studies Low
  16 Additional analyses Low
Results 17 Study selection of the key findings High
  18 Study characteristics or statistical presentations High
  19 Risk of bias within studies Low
  20 Results of individual studies or graphs and tabular presentations High
  21 Synthesis of results Low
  22 Risk of bias across studies Low
  23 Additional analysis Low
Discussion 24 Summary of evidence Moderate
  25 Limitations High
  26 Conclusions High
Funding 27 Information about funding or author conflict Low

Steps of forming the PRISMA framework

Step 1: Identify the papers on the basis of search strategies and the relevant databases used for searching and collecting research papers. The most common databases of literature include:

  • Google Scholar,
  • Embase,
  • IEEE Xplore,
  • EBSCO,
  • Cochrane and,
  • PubMed.

The first step does not involve the inclusion or exclusion of papers.

Step 2: Screening the papers will involve using the quality checklist in stages. The first screening uses both the inclusion or exclusion criteria and the quality checklist to exclude the irrelevant papers.

Step 3: Check if the title of the papers found is corroborating the current study. In addition, include or exclude papers on the basis of the availability of full-text papers.

Step 4: Then check if the papers are in their specified language. Most scholars use English; however others may use their local languages like French, Japanese, Spanish and others. Inclusion or exclusion of papers are in this step also seeks to identify duplicate papers. This step only checks the 1st and 2nd checklist items.

Step 5: The main and the most important step is the Eligibility of the papers. Prioritize using the quality checklist in finding the eligibility of the papers. Use all or some of the checklist items on the basis of the criticalness of the papers.

Step 6: The last step involves critically reviewing the papers to address the aim of the current study.

The PRISMA flowchart (Moher, 2013)
The PRISMA flowchart (Moher, 2013)

Preparing the PRISMA flowchart

1. Identify the total number of papers collected from different papers and mention the sources.

2. Presenting the excluded and the included from the 1st screening and mention the reason for exclusion.

3. Again presenting the excluded papers while keeping in count that the number of included papers now is n=2153. Check the eligibility of the papers elected on the basis of the quality checklist items and present the reason for excluding the papers.

4. Repeat the step if needed where the number of papers included stands at 368.

5. Present the final number of papers included.

6. Include the eligibility and screening test again if the study further focuses on Meta-analysis.




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