Repeated meta-analyses: Members of Cochrane and others have developed techniques to manage Type I and II errors that can occur over time by updating and repeating meta-analyses. Cochrane has provided funding for a review of these techniques undertaken by Mark Simmonds at York University and other members of the Statistical Methods Group. Two principle techniques emerge as controlling for these errors: Trials Sequential Analysis and Sequential Meta-analysis. Further detailed information is available [see full statement below]. Some review authors have used these techniques, we do not currently encourage or discourage their use at this point.
Cochrane Scientific Committee recommendation: Further technical examination of these two approaches is required before the Committee can decide whether there is a preferred approach or whether the methods provide added value to managing random error. An expert panel established will discuss further and report back to the Committee before arriving at a final decision. (Full statement)