An Example of Mediation

Students were randomized to an experimental condition that encouraged them to study for a test or to a control condition. Those in the experimental group spent more time studying for the test in comparison with those in the control group.

Mediator in question: Hours spent studying for the test

A Mediator

• explains an intermediate process that transmits the impact of a risk factor or an intervention on an outcome. Hence it answers the question of WHY.
• “represents the generative mechanism through which the focal independent variable is able to influence the dependent variable of interest” (Baron & Kenny, 1986, p.1173).

A Mediation Analysis

• reveals WHY a risk factor or an intervention generates (or fails to generate) an impact.