What do main effects in meta-analysis typically represent?

In the context of meta-analysis, main effects refer to the overall outcomes of treatment, capturing the average effect of an intervention across multiple studies or data sources. This overall effect is derived from the aggregated data, which helps to determine the efficacy or impact of a particular treatment or intervention on a specific outcome. Main effects focus on the common findings across various studies, allowing researchers to synthesize the results and draw conclusions about the effectiveness of the treatment being analyzed.

By comparing different studies in a meta-analysis, the main effect provides a clear estimation of how a treatment influences outcomes, guiding clinical decisions and policy-making. It emphasizes the collective evidence gathered from varying contexts and participant characteristics, thus providing a comprehensive view of treatment effects. This makes main effects a crucial component in understanding the generalizability of research findings in clinical practice.