# Chapter 3 The Simple Mediation Model

Hayes closed the opening with:

Whereas answering questions about when or for whom is the domain of moderation analysis, questions that ask about how pertain to mediation, the focus of this and the next three chapters. In this chapter, [we’ll explore] the simple mediation model and illustrate using OLS regression-based Bayesian path analysis how the effect of an antecedent variable $$X$$ on some final consequent $$Y$$ can be partitioned into two paths of influence, direct and indirect.