Case
Abstract
Meta-analysis can provide a reliable overall estimate of the effect of an intervention by combining all of the available individual study evidence. Although there are an ever-increasing number of published meta-analyses, journal word limits mean that the numerous practical challenges involved in producing the final review are usually not documented. This case study is an attempt to identify these types of challenges using a concrete example of a real meta-analysis examining hypnotic interventions for pain. Specific strategies that can be used to help tackle these challenges are outlined, including preparation of a detailed study protocol, how to approach tricky screening and extraction decisions, computing effect sizes when data are not presented in conventional form, and the importance of assembling a suitable research team. This case does not describe the methodological principles of meta-analysis for which there are many excellent existing texts. Instead, it can be used as a complementary guide to these texts as it highlights the type of practical challenges that we faced and suggests possible ways to combat them that we hope will be useful to others.