Mediation

Week 11: March 17, 2025

Today’s Reading

  • Hayes Chapter 3

Introduction to the Topic

This week, we explore mediation analysis, a statistical approach used to understand the mechanisms through which an independent variable influences a dependent variable via a third variable, known as the mediator. Mediation analysis is essential for uncovering causal pathways in research.


Key Concepts:

  • Direct Effects: The relationship between the independent variable and the dependent variable, excluding the mediator.
  • Indirect Effects: The portion of the relationship explained through the mediator.
  • Total Effects: The combined impact of direct and indirect effects.
  • Bootstrapping: A resampling method for testing the significance of indirect effects.

Relevance:

  • Students will learn how to identify and test mediating variables in a causal framework.
  • Students will explore how to decompose total effects into direct and indirect components to better understand relationships among variables.

Why This Is Important:

  • Mediation analysis allows researchers to move beyond simple relationships to uncover how and why effects occur.
  • Understanding mediation is critical for testing theoretical models in fields like psychology, sociology, and public health.

How This Ties Into the Overall Course:

  • Builds upon previous topics, such as regression and effect sizes, by extending these tools to explore causal pathways.
  • Prepares students for advanced concepts like moderated mediation and structural equation modeling (SEM), where mediation analysis is a core component.

By the end of this week, students will be able to conduct mediation analyses, interpret direct and indirect effects, and evaluate the significance of mediators using bootstrapping methods.

Class Files

Class Files

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R Code

Data Sets

Resources

Today’s Reading

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Additional Notes