Cumulating evidence from randomized trials: utilizing sequential monitoring boundaries for cumulative meta-analysis

We propose the adaptation of classical monitoring boundaries for use in cumulative meta-analysis as guidelines for deciding when accumulating evidence is statistically significant and medically convincing. The interpretation of information from a randomized controlled trial is compared with that from a meta-analysis. The concept of optimal information size for a meta-analysis is developed and used to adapt monitoring boundaries to cumulative meta-analysis.