Table Of Contentebook
THE GUILFORD PRESS
Doing Statistical Mediation and Moderation
Methodology in the Social Sciences
David A. Kenny, Founding Editor
Todd D. Little, Series Editor
www.guilford.com/MSS
This series provides applied researchers and students with analysis and research
design books that emphasize the use of methods to answer research questions.
Rather than emphasizing statistical theory, each volume in the series illustrates when
a technique should (and should not) be used and how the output from available
software programs should (and should not) be interpreted. Common pitfalls as well as
areas of further development are clearly articulated.
RECENT VOLUMES
DIAGNOSTIC MEASUREMENT: ThEORy, METhODS, AND AppLICATIONS
André A. Rupp, Jonathan Templin, and Robert A. Henson
ADVANCES IN CONFIGURAL FREQUENCy ANALySIS
Alexander von Eye, Patrick Mair, and Eun-Young Mun
AppLIED MISSING DATA ANALySIS
Craig K. Enders
pRINCIpLES AND pRACTICE OF STRUCTURAL EQUATION MODELING,
ThIRD EDITION
Rex B. Kline
AppLIED META-ANALySIS FOR SOCIAL SCIENCE RESEARCh
Noel A. Card
DATA ANALySIS WITh Mplus
Christian Geiser
INTENSIVE LONGITUDINAL METhODS: AN INTRODUCTION TO DIARy
AND ExpERIENCE SAMpLING RESEARCh
Niall Bolger and Jean-Philippe Laurenceau
DOING STATISTICAL MEDIATION AND MODERATION
Paul E. Jose
LONGITUDINAL STRUCTURAL EQUATION MODELING
Todd D. Little
INTRODUCTION TO MEDIATION, MODERATION, AND CONDITIONAL
pROCESS ANALySIS: A REGRESSION-BASED AppROACh
Andrew F. Hayes
Doing Statistical Mediation
and Moderation
paul E. Jose
Series Editor’s Note by Todd D. Little
ThE GUILFORD pRESS
New york London
© 2013 The Guilford Press
A Division of Guilford Publications, Inc.
72 Spring Street, New York, NY 10012
www.guilford.com
All rights reserved
No part of this book may be reproduced, translated, stored in a retrieval
system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, microfilming, recording, or otherwise, without written
permission from the publisher.
Printed in the United States of America
This book is printed on acid-free paper.
Last digit is print number: 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data
Jose, Paul E. (Paul Easton), 1952–
Doing statistical mediation and moderation / Paul E. Jose.
p. cm. — (Methodology in the social sciences)
Includes bibliographical references and index.
ISBN 978-1-4625-0815-0 (pbk.) — ISBN 978-1-4625-0821-1 (hardcover)
1. Mediation (Statistics) 2. Social sciences—Statistical methods. I. Title.
QA278.2.J67 2013
519.5′36—dc23
2012047804
To my wife, Mary, and to my three sons, Ben, Easton,
and Isaac, who have had to tolerate many hours of
“I’ve got to work on my book now” instead of time with me
doing other, more enjoyable family things
My wife’s enduring support, love, and belief in me
has sustained me through many hours of hard work,
and my sons remind me to enjoy and savor the journey
through life.
Series Editor’s Note
Mediation and moderation are two ubiquitous concepts in social and behav-
ioral science research. These concepts pervade the hypotheses of researchers
from the world of business to the realm of education. Given their common
invocation in the theories and hypotheses of researchers, one would think
that the meanings of mediation and moderation would be well understood
and that their distinction would be clear and never conflated. Unfortunately,
they are oft confused and researchers appear rather perplexed about how to
define and test for evidence of their influence. Enter Paul Jose’s book, Doing
Statistical Mediation and Moderation.
I am delighted to introduce this book to you. I first met Paul at one of our
very first Kansas University Stats Camps held every June (see crmda.KU.edu
for more details on this annual event). Paul was there to hone his skills on
recent advances in structural equation modeling. The enthusiasm that he
shared with us on his interest in writing a book on mediation and modera-
tion was inspiring. A few years later, when I took the helm of The Guilford
Press Methodology in the Social Sciences Series from David Kenny, I solicited
Paul to bring his dream to the series. Paul has pitched this book precisely at
the level that I hoped he would. It is a disarming treatment of the sometimes
intimidating concepts of mediation and moderation. His writing style is a
reflection of his kind personality, wry wit, and statistical scholarship. He
brings you in for an enjoyable learning experience, employing a terrific bal-
ance of humor and active voice with just the right dosage of how-to procedure
and postresults interpretation. The book does not require more than a basic
understanding of statistics because Paul is careful to introduce and define
concepts along the way.
vii
viii Series Editor’s Note
Paul emphasizes that there are more than two ways to analyze data with
three variables—for example, a third way is simple additive effects. As Paul
outlines, moderator-oriented research is more interested in when certain
effects will hold. In contrast, mediator-oriented research is more interested
in the mechanisms of how and why effects occur. A moderator is often intro-
duced when X and Y have a weak or inconsistent relationship. In contrast,
a mediator is often introduced when X and Y have a strong relationship to
start with. As I mentioned, researchers often confuse these ideas. They also
conflate them with simple additive effects of multiple predictors! Here, the
additive effect is the simple linear combination of unique effects that con-
tribute to an outcome. In my consultations with others, I frequently have to
help them understand that one’s standing on an outcome can directly relate
to one’s standing on the multiple predictors, with nothing being mediated
or moderated. That is, researchers often confuse how different people can
have different profiles on the independent variables, which lead to the same
or different outcome with none of the process being related to mediation or
moderation. I like that Paul cautions readers and researchers that not all mul-
tivariate problems are mediated or moderated processes. The outcome can be
multiply caused. Now, with this book, I have a definitive resource that I can
share with researchers to help them understand these essential distinctions.
The bottom line is, kudos to Paul. After enjoying his book, you not only
will finally get the distinction between a mediator and a moderator squared
away and know how to properly test for the existence of a mediator or a
moderator, you will also more deftly understand the complexities of such
processes as mediated moderation and moderated mediation.
Todd d. LiTTLe
Postconferencing in Edmonton, Alberta
