Meta-analysis: neither quick nor easy.
BACKGROUND
Meta-analysis is often considered to be a simple way to summarize the existing literature. In this paper we describe how a meta-analysis resembles a conventional study, requiring a written protocol with design elements that parallel those of a record review.


METHODS
The paper provides a structure for creating a meta-analysis protocol. Some guidelines for measurement of the quality of papers are given. A brief overview of statistical considerations is included. Four papers are reviewed as examples. The examples generally followed the guidelines we specify in reporting the studies and results, but in some of the papers there was insufficient information on the meta-analysis process.


CONCLUSIONS
Meta-analysis can be a very useful method to summarize data across many studies, but it requires careful thought, planning and implementation.
Berman
Nancy G
NG
Department of Pediatrics, Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, CA, USA. berman@gcrc.rei.edu
Parker
Robert A
RA
D003625:Data Collection; D003710:Demography; D017408:Guidelines as Topic; D006801:Humans; D015201:Meta-Analysis as Topic; D016896:Treatment Outcome