Cochrane reviews on the effects of interventions vary considerably in their scope. Some reviews compare two interventions, while others examine the comparative effectiveness of many or all available interventions for a given condition. When the comparative effectiveness of a range of interventions is of interest, a number of appropriate statistical methodologies are available to be used for analysis (Li 2011).

Cochrane Review Groups are encouraged to consult the Comparing Multiple Interventions Methods Group (CMIMG) when undertaking a conventional Intervention review or an Overview of systematic reviews that aims to simultaneously compare multiple interventions. The review teams should involve a statistician or methodologist with expertise in the techniques (e.g., indirect comparison or network meta-analysis) if these are likely to be employed.

The CMIMG offers methodological peer review support for titles, protocols, and review manuscripts that explicitly state that their objective is to compare multiple interventions, and therefore an indirect comparison and/or network meta-analysis is likely to be used.

The peer review request should be sent to Tianjing Li (tli@jhsph.edu), Co-Convenor of the CMIMG. In the request, please describe in sufficient detail (1) the type of review (e.g., intervention review or Overview of reviews); (2) whether the authors aim to simultaneously compare multiple interventions for a given condition; (3) whether the authors foresee that an indirect comparison and/or network meta-analysis will be employed; and (4) whether statistical support is needed and is likely to be substantial.

Given the limited resources we have at the moment, the CMIMG will help to identify methodologists who can either provide comments, or get involved in the review based on the review team’s need for expertise. However, it would be the Review Group’s responsibility to communicate with the methodologist and arrange an agreeable timeframe for getting the comments back. When a review team is working closely with a methodologist designated by the CMIMG, authorship should be offered to the methodologist if the amount of support is considered to be substantial and meets accepted criteria for authorship.