Introduction to systematic reviews and meta-analysis

Respirology. 2016 May;21(4):626-37. doi: 10.1111/resp.12783.


Systematic reviews provide a method for collating and synthesizing research, and are used to inform healthcare decision making by clinicians, consumers and policy makers. A core component of many systematic reviews is a meta-analysis, which is a statistical synthesis of results across studies. In this review article, we introduce meta-analysis, focusing on the different meta-analysis models, their interpretation, how a model should be selected and discuss potential threats to the validity of meta-analyses. We illustrate the application of meta-analysis using data from a review examining the effects of early use of inhaled corticosteroids in the emergency department treatment of acute asthma.

Keywords: fixed effect model; meta-analysis; random effects model; systematic review; tutorial.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenal Cortex Hormones
  • Asthma
  • Computational Biology / trends*
  • Decision Support Systems, Clinical / trends*
  • Emergency Service, Hospital / statistics & numerical data*
  • Evidence-Based Medicine
  • Humans
  • Information Dissemination / methods*
  • Meta-Analysis as Topic
  • Pulmonary Medicine*
  • Randomized Controlled Trials as Topic
  • Review Literature as Topic
  • Treatment Outcome


  • Adrenal Cortex Hormones