advanced-literature-synthesis

Define a PICO research question, register a protocol with PROSPERO, build a transparent search strategy across databases, screen studies with two reviewers, appraise quality, extract data with standardized forms, and report using the PRISMA checklist and flow diagram.

Meta-analysis statistically pools effect sizes from quantitative studies measuring comparable outcomes. Meta-synthesis integrates findings from qualitative studies through approaches like thematic synthesis or meta-ethnography to build interpretive understanding.

Use evidence mapping when a topic is too broad for a single systematic review, evidence is scattered, or the goal is a landscape overview and gap identification rather than a pooled effect estimate. It covers 50 to 200+ studies with less depth per study.

I² measures the proportion of effect size variability due to differences between studies. Values under 25% indicate low heterogeneity suitable for fixed-effects models; above 50% warrants random-effects models, subgroup analysis, or meta-regression.

At least 5 studies with comparable, extractable effect size data are needed for a meaningful meta-analysis. For qualitative meta-synthesis, a minimum of about 8 studies is recommended for meaningful synthesis.

Create a funnel plot to visually inspect asymmetry, run Egger's test where p < 0.05 suggests bias, and apply trim-and-fill analysis to estimate missing studies and test whether conclusions survive adjustment.