Library Guides: Meta-analyses: Introduction

Types of meta-analyses

There are two main types of meta-analyses:

Standard meta-analysis that combines results of multiple studies based on one question or problem
"Network meta-analysis compares multiple interventions simultaneously by analyzing studies making different comparisons in the same analysis." (Source: Petticrew et al., 2013)
Network meta-analyses may also be known as a NMA, MTC Meta-Analysis, Multiple Treatment Meta-Analysis, Mixed Treatments Comparison, Multiple Treatments Comparison, Pair-Wise Meta-Analysis, Indirect Treatment Comparison, Multiple Treatment Comparison Meta-Analysis, Live Cumulative Network Analysis (Source: Temple University Libraries, 2021)

Advantages	Limitations
Provides a comparison between many different studies to summarise outcomes. This may also help explore and resolve controversies between different study outcomes.	Results may be misleading if differences in study designs, biases within studies, differences across studies and reporting biases aren't identified and considered (Deeks et al., 2021)
Provides a larger data set when many smaller studies are combines to see larger effect sizes.	Data may be missing from published studies that skew the results of the analysis.
May provide answers to questions not answered in individual studies.	As often only published studies are included in the meta-analysis not all data on the topic may be included. Publication bias includes cases where only publishing studies with statistically significant results, or only reporting on parts of studies that have statistical significance.
	Use of inappropriate statistical methods for meta-analysis may skew the results of the meta-analysis.