METAN: Stata module for fixed and random effects meta-analysis

These routines provide facilities to conduct meta-analyses of data from more than one study and to graph the results. Either binary (event) or continuous data from two groups may be combined using the metan command. Additionally, intervention effect estimates with corresponding standard errors or confidence intervals may be meta-analysed. Recently added facilities include by() processing and an update to Stata 9 graphics. This is an updated version of metan as published in STB-44, authored by Michael J Bradburn, Jonathan J Deeks, Douglas G Altman. The package includes a command to produce funnel plots to assess small study effects, and L'Abbe plots to examine whether the assumption of a common odds ratio, risk ratio or risk difference is reasonable. Also included is the metannt program for binary data, which displays estimated intervention effects in terms of the absolute reduction in risk and number needed to treat. A description of available Stata meta-analysis commands may be found at http://www.stata.com/support/faqs/stat/meta.html.