Meta-analysis 101: what you want to know in the era of comparative effectiveness.

In the era of "comparative effectiveness" research, each of the major stakeholders in healthcare-payors, patients, providers, and government-face a similar challenge. When making a decision about whether a new device, drug, or a diagnostic modality should be considered for use or coverage, what choices are best supported by the evidence? Medical evidence is defined by randomized controlled trials and by observational studies that vary greatly in their design, the accuracy of their analyses, and the relevance of their conclusions and recommendations. Hence, key decision makers increasingly rely on systematic reviews and meta-analyses to facilitate the interpretation and application of research evidence. Knowing how to evaluate meta-analyses and understanding the potential pitfalls of the method are crucial for those involved in designing drug benefits. The authors highlight the process, strengths, and weaknesses of meta-analysis and explain how to judge the value of the results.