Systematic Literature Review (PRISMA)

Systematic Literature Review (PRISMA)

Overview

A systematic review uses explicit, pre-defined methods to identify, select, appraise, and synthesize all relevant research on a specific question. Unlike narrative reviews, systematic reviews follow a reproducible protocol that minimizes bias in study selection and interpretation. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework provides the standard reporting structure, including the iconic flow diagram tracking records through identification, screening, eligibility, and inclusion.

When to Use

• Synthesizing the totality of evidence on a well-defined research question
• Identifying gaps, contradictions, or consensus in a body of literature
• Establishing what is known before designing new empirical research
• Informing policy or practice guidelines with evidence-based synthesis

When NOT to Use

• When the research question is too broad to define clear inclusion criteria
• When a scoping review (mapping the landscape) is more appropriate than a systematic review (answering a specific question)
• When time constraints prevent the rigorous protocol required
• When there is very little published research on the topic (consider a scoping review first)

Assumptions

IRON LAW: A systematic review must be REPRODUCIBLE — every search
decision, inclusion criterion, and quality assessment must be documented
so another researcher can replicate the process. If your review cannot
be replicated, it is a narrative review, NOT a systematic review.

Key assumptions:

1. Transparency and reproducibility distinguish systematic from narrative reviews
2. A pre-registered protocol reduces bias in study selection and analysis
3. At least two independent reviewers should screen and assess studies to reduce subjective bias
4. Quality assessment of included studies is mandatory — not all evidence is equal

Methodology

Step 1: Define the Research Question and Protocol

Formulate a focused question using a framework (PICO for interventions, PEO for qualitative, SPIDER for mixed methods). Register the protocol (e.g., PROSPERO). Define databases, search terms, date ranges, and language restrictions.