Mediation analysis is a method that quantifies how health exposures, such as medical interventions, change patient outcomes. Evidence that is generated from mediation analyses is important for intervention development and clinical and policy decision making. Mediation analysis has many applications that require specific and careful consideration for design, conduct, analysis, and interpretation. This article outlines motivations, effect types, causal assumptions, estimation, and reporting guidance for mediation analysis studies that aim to improve their conduct, interpretation, and implementation.
The reasons that health exposures, such as medical interventions, change patient outcomes are often poorly understood. Health exposures change patient outcomes through biological, psychological, and social mediators. Generally, a mediator is a variable that lies on the causal path between an exposure and an outcome. The causal role of a mediator can be communicated through a directed acyclic