They come in the form of systematic reviews and literature reviews and are a form of secondary literature.[4] Systematic reviews determine an objective list of criteria, and find all previously published original experimental papers that meet the criteria. They then compare the results presented in these papers. Literature reviews, by contrast, provide a summary of what the authors believe are the best and most relevant prior publications.
1. Systematic Review
What it is: A structured, reproducible review that answers a specific research question by comprehensively identifying, selecting, and critically appraising relevant studies.
Key characteristics
- Predefined protocol (often PRISMA)
- Explicit search strategy & inclusion/exclusion criteria
- Quality/risk-of-bias assessment
- Can be qualitative only or include meta-analysis
Output
- Synthesized evidence (narrative and/or quantitative)
2. Meta-analysis
What it is:
A statistical technique that quantitatively combines results from multiple comparable studies.
Key characteristics
- Requires numerical outcomes (effect sizes)
- Uses statistical models (fixed/random effects)
- Produces pooled estimates, confidence intervals, heterogeneity (I²)
Important
- Meta-analysis is usually part of a systematic review, not a standalone concept.
Output
- Forest plots, pooled effect sizes
3. Review Article (Narrative Review)
What it is:
A broad, descriptive overview of a topic based on selected literature, often reflecting expert perspective.
Key characteristics
- No strict protocol
- Search strategy may be implicit or absent
- More interpretive and conceptual
- Faster to write, but less reproducible
Output
- Thematic discussion, trends, gaps, future directions
When to Use Which
- Review article → Introduce a field, identify trends, motivate research
- Systematic review → Evidence-based conclusions, research gaps
- Systematic review + meta-analysis → Strongest empirical evidence (common in top journals)
One-sentence takeaway
A meta-analysis is a statistical method, a systematic review is a rigorous process, and a review article is a broad scholarly overview. review is a rigorous process, and a review article is a broad scholarly overview.
A meta-analysis is a statistical method, a systematic review is a rigorous process, and a review article is a broad scholarly overview.
f optimization techniques in
