About the Book
Explaining the fundamentals of mediation and moderation analysis, this engaging book also shows how to integrate the two using an innovative strategy known as conditional process analysis. Procedures are described for testing hypotheses about the mechanisms by which causal effects operate, the conditions under which they occur, and the moderation of mechanisms. Relying on the principles of ordinary least squares regression, Andrew Hayes carefully explains the estimation and interpretation of direct and indirect effects, probing and visualization of interactions, and testing of questions about moderated mediation. Examples using data from published studies illustrate how to conduct and report the analyses described in the book. Of special value, the book introduces and documents PROCESS, a macro for SPSS and SAS that does all the computations described in the book. The companion website (www.afhayes.com) offers free downloads of PROCESS plus data files for the book's examples.
Unique features include:
*Compelling examples (presumed media influence, sex discrimination in the workplace, and more) with real data; boxes with SAS, SPSS, and PROCESS code; and loads of tips, including how to report mediation, moderation and conditional process analyses.
*Appendix that presents documentation on use and features of PROCESS.
*Online supplement providing data, code, and syntax for the book's examples.
Table of Contents:
I. FUNDAMENTAL CONCEPTS
1. Introduction
1.1. A Scientist in Training
1.2. Questions of Whether, If, How, and When
1.3. Conditional Process Analysis
1.4. Correlation, Causality, and Statistical Modeling
1.5. Statistical Software
1.6. Overview of this Book
1.7. Chapter Summary
2. Simple Linear Regression
2.1. Correlation and Prediction
2.2. The Simple Linear Regression Equation
2.3. Statistical Inference
2.4. Assumptions for Interpretation and Statistical Inference
2.5. Chapter Summary
3. Multiple Linear Regression
3.1. The Multiple Linear Regression Equation
3.2. Partial Association and Statistical Control
3.3. Statistical Inference in Multiple Regression
3.4. Statistical and Conceptual Diagrams
3.5. Chapter Summary
II. MEDIATION ANALYSIS
4. The Simple Mediation Model
4.1. The Simple Mediation Model
4.2. Estimation of the Direct, Indirect, and Total Effects of X
4.3. Example with Dichotomous X: The Influence of Presumed Media Influence
4.4. Statistical Inference
4.5. An Example with Continuous X: Economic Stress among Small Business Owners
4.6. Chapter Summary
5. Multiple Mediator Models
5.1. The Parallel Multiple Mediator Model
5.2. Example Using the Presumed Media Influence Study
5.3. Statistical Inference
5.4. The Serial Multiple Mediator Model
5.5. Complementarity and Competition among Mediators
5.6. OLS Regression versus Structural Equation Modeling
5.7. Chapter Summary
III. MODERATION ANALYSIS
6. Miscellaneous Topics in Mediation Analysis
6.1. What About Baron and Kenny?
6.2. Confounding and Causal Order
6.3. Effect Size
6.4. Multiple Xs or Ys: Analyze Separately or Simultaneously?
6.5. Reporting a Mediation Analysis
6.6. Chapter Summary
7. Fundamentals of Moderation Analysis
7.1. Conditional and Unconditional Effects
7.2. An Example: Sex Discrimination in the Workplace
7.3. Visualizing Moderation
7.4. Probing an Interaction
7.5. Chapter Summary
8. Extending Moderation Analysis Principles
8.1. Moderation Involving a Dichotomous Moderator
8.2. Interaction between Two Quantitative Variables
8.3. Hierarchical versus Simultaneous Variable Entry
8.4. The Equivalence between Moderated Regression Analysis and a 2 × 2 Factorial Analysis of Variance
8.5. Chapter Summary
9. Miscellaneous Topics in Moderation Analysis
9.1. Truths and Myths about Mean Centering
9.2. The Estimation and Interpretation of Standardized Regression Coefficients in a Moderation Analysis
9.3. Artificial Categorization and Subgroups Analysis
9.4. More Than One Moderator
9.5. Reporting a Moderation Analysis
9.6. Chapter Summary
IV. CONDITIONAL PROCESS ANALYSIS
10. Conditional Process Analysis
10.1. Examples of Conditional Process Models in the Literature
10.2. Conditional Direct and Indirect Effects
10.3. Example: Hiding Your Feelings from Your Work Team
10.4. Statistical Inference
10.5. Conditional Process Analysis in PROCESS
10.6. Chapter Summary
11. Further Examples of Conditional Process Analysis
11.1. Revisiting the Sexual Discrimination Study
11.2. Moderation of the Direct and Indirect Effects in a Conditional Process Model
11.3. Visualizing the Direct and Indirect Effects
11.4. Mediated Moderation
11.5. Chapter Summary
12. Miscellaneous Topics in Conditional Process Analysis
12.1. A Strategy for Approaching Your Analysis
12.2. Can a Variable Simultaneously Mediate and Moderate Another Variable’s Effect?
12.3. Comparing Conditional Indirect Effects and a Formal Test of Moderated Mediation
12.4. The Pitfalls of Subgroups Analysis
12.5. Writing about Conditional Process Modeling
12.6. Chapter Summary
Appendix A. Using PROCESS
Appendix B. Monte Carlo Confidence Intervals in SPSS and SAS
About the Author :
Andrew F. Hayes, PhD, is Professor of Quantitative Psychology at The Ohio State University. His research and writing on data analysis has been published widely. Dr. Hayes is the author of Introduction to Mediation, Moderation, and Conditional Process Analysis and Statistical Methods for Communication Science, as well as coauthor, with Richard B. Darlington, of Regression Analysis and Linear Models. He teaches data analysis, primarily at the graduate level, and frequently conducts workshops on statistical analysis throughout the world. His website is www.afhayes.com.
Review :
"Mediation and moderation are two of the most widely used statistical tools in the social sciences. Students and experienced researchers have been waiting for a clear, engaging, and comprehensive book on these topics for years, but the wait has been worth it--this book is an absolute winner. With his usual clarity, Hayes has written what will become the default resource on mediation and moderation for many years to come."--Andy Field, PhD, School of Psychology, University of Sussex, United Kingdom
"Hayes provides an accessible, thorough introduction to the analysis of models containing mediators, moderators, or both. The text is easy to follow and written at a level appropriate for an introductory graduate course on mediation and moderation analysis. The book is also an extremely useful resource for applied researchers interested in analyzing conditional process models. One strength is the inclusion of numerous examples using real data, with step-by-step instructions for analysis of the data and interpretation of the results. This book's largest contribution to the field is its replacement of the confusing terminology of mediated moderation and moderated mediation with the clearer and broader term conditional process model."--Matthew Fritz, PhD, Department of Educational Psychology, University of Nebraska-Lincoln
"A welcome contribution. This book's accessible language and diverse set of examples will appeal to a wide variety of substantive researchers looking to explore how or why, and under what conditions, relationships among variables exist. Hayes has a unique ability to effectively communicate technical material to nontechnical audiences. He facilitates application of several cutting-edge statistical models by providing practical, well-oiled machinery for conducting the analyses in practice. I can use this book to enhance my graduate-level mediation class by extending the course to include more coverage on differentiating mediation versus moderation and on conditional process models that simultaneously evaluate both effects together."--Amanda Jane Fairchild, PhD, Department of Psychology, University of South Carolina
"This decidedly readable, informative book is perfectly suited for a range of audiences, from the novice graduate student not quite ready for SEM to the advanced statistics instructor. Even the seasoned quantitative methodologist will benefit from Hayes's years of accumulated wisdom as he expertly navigates this burgeoning--and at times inconsistent--literature. This book is particularly well suited for graduate-level courses. Hayes brings conditional process analysis to life with such passion that even the most 'stat-o-phobic' will become convinced that they too can master SPSS (or SAS) process. The thoughtful use of real-life examples, accompanied by SPSS and SAS syntax and output, makes the book highly accessible."--Shelley Brown, PhD, Department of Psychology, Carleton University, Canada
"Mediation and moderation are two of the most widely used statistical tools in the social sciences. Students and experienced researchers have been waiting for a clear, engaging, and comprehensive book on these topics for years, but the wait has been worth it--this book is an absolute winner. With his usual clarity, Hayes has written what will become the default resource on mediation and moderation for many years to come." - Andy Field, PhD, School of Psychology, University of Sussex, United Kingdom
"Hayes provides an accessible, thorough introduction to the analysis of models containing mediators, moderators, or both. The text is easy to follow and written at a level appropriate for an introductory graduate course on mediation and moderation analysis. The book is also an extremely useful resource for applied researchers interested in analyzing conditional process models. One strength is the inclusion of numerous examples using real data, with step-by-step instructions for analysis of the data and interpretation of the results. This book's largest contribution to the field is its replacement of the confusing terminology of mediated moderation and moderated mediation with the clearer and broader term conditional process model." - Matthew Fritz, PhD, Virginia Polytechnic Institute and State University, USA
"A welcome contribution. This book's accessible language and diverse set of examples will appeal to a wide variety of substantive researchers looking to explore how or why, and under what conditions, relationships among variables exist. Hayes has a unique ability to effectively communicate technical material to nontechnical audiences. He facilitates application of several cutting-edge statistical models by providing practical, well-oiled machinery for conducting the analyses in practice. I can use this book to enhance my graduate-level mediation class by extending the course to include more coverage on differentiating mediation versus moderation and on conditional process models that simultaneously evaluate both effects together." - Amanda Jane Fairchild, PhD, University of South Carolina, USA
"This decidedly readable, informative book is perfectly suited for a range of audiences, from the novice graduate student not quite ready for SEM to the advanced statistics instructor. Even the seasoned quantitative methodologist will benefit from Hayes's years of accumulated wisdom as he expertly navigates this burgeoning - and at times inconsistent/m-/literature. This book is particularly well suited for graduate-level courses. Hayes brings conditional process analysis to life with such passion that even the most 'stat-o-phobic' will become convinced that they too can master SPSS (or SAS) process. The thoughtful use of real-life examples, accompanied by SPSS and SAS syntax and output, makes the book highly accessible." - Shelley Brown, PhD, Carleton University, Canada
