Moderators and Mediators in Treatment Outcome Studies of Childhood Disorders: The What, Why, and How

This chapter is an introduction to the book Moderators and Mediators of Youth Treatment Outcomes. The chapter provides definitions and a graphical representation of the so-called “third variables” thought to alter associations between youth treatments and treatment outcomes. Predictors, moderators, and mediators are discussed, as well as the most important conceptual issues related to the investigation of moderating and mediating variables in the context of youth psychotherapy research. Challenges associated with design and statistical issues are outlined and solutions provided. The chapter concludes with descriptions of more complex moderation and mediation models, and research designs that can be implemented and that have the potential of enhancing treatment outcomes.