Abstract
Mediated moderation occurs when the interaction between two variables affects a mediator, which then affects a dependent variable. In this article, we describe the mediated moderation model and evaluate it with a statistical simulation using an adaptation of product-of-coefficients methods to assess mediation. We also demonstrate the use of this method with a substantive example from the adolescent tobacco literature. In the simulation, relative bias (RB) in point estimates and standard errors did not exceed problematic levels of ±10%, although systematic variability in RB was accounted for by parameter size, sample size, and nonzero direct effects. Power to detect mediated moderation effects appears to be severely compromised under one particular combination of conditions: when the component variables that make up the interaction terms are correlated and partial mediated moderation exists. Implications for the estimation of mediated moderation effects in experimental and nonexperimental research are discussed.
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Aiken, L. S., &West, S. G. (1991).Multiple regression: Testing and interpreting interactions. Newbury Park, CA: Sage.
Baron, R. M., &Kenny, D. A. (1986). The moderator-mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations.Journal of Personality & Social Psychology,51, 1173–1182.
Bentler, P. M. (1995).EQS structural equations program manual. Los Angeles: Multivariate Software.
Bishop, Y. M. M., Fienberg, S. E., &Holland, P. W. (1975).Discrete multivariate analysis: Theory and practice. Cambridge, MA: MIT Press.
Bollen, K. A. (1989).Structural equations with latent variables. New York: Wiley.
Castro, F. G., Coe, K., Gutierres, S., &Saenz, D. (1996). Designing health promotion programs for Latinos. In P. M. Kato & T. Mann (Eds.),Handbook of diversity issues in health psychology (pp. 319–345). New York: Plenum.
Castro, F. G., De Anda, M. E., Abeita, L. A., & Morgan-Lopez, A. A. (1999, August).Healthy lifestyle I: Culturally-oriented tobacco prevention with Mexican American youth. Paper presented at the 107th meeting of the American Psychological Association, Boston.
Chen, H.-T. (1990).Theory-driven evaluations. Newbury Park, CA: Sage.
Donaldson, S. I. (2001). Mediator and moderator analysis in program development. In S. Sussman (Ed.),Handbook of program development for health behavior research and practice (pp. 470–496). Thousand Oaks, CA: Sage.
James, L. R., &Brett, J. M. (1984). Mediators, moderators and tests for mediation.Journal of Applied Psychology,69, 307–321.
Johnson, R. A., &Wichern, D. W. (2002).Applied multivariate statistical analysis. Upper Saddle River, NJ: Prentice Hall.
Jöreskog, K. G., &Sörbom, D. (1996).LISREL 8 user’s reference guide. Chicago: Scientific Software International.
Lipsey, M. W. (1993). Theory as method: Small theories of treatments. In L. B. Sechrest & A. G. Scott (Eds.),Understanding causes and generalizing about them (pp. 5–38). San Francisco: Jossey-Bass.
MacKinnon, D. P. (1994). Analysis of mediating variables in prevention intervention studies. In A. Cazares & L. A. Beatty (Eds.),Scientific methods for prevention intervention research (DHHS Publication No. 94–3631, pp. 127–153). Washington, DC: U.S. Department of Health and Human Services.
MacKinnon, D. P., &Dwyer, J. H. (1993). Estimating mediated effects in prevention studies.Evaluation Review,17, 144–158.
MacKinnon, D. P., Johnson, C. A., Pentz, M. A., Dwyer, J. H., Hansen, W. B., Flay, B. R., &Wang, E. Y. (1991). Mediating mechanisms in a school-based drug prevention program: First-year effects of the Midwestern Prevention Project.Health Psychology,10, 164–172.
MacKinnon, D. P., Lockwood, C. M., Hoffman, J. M., West, S. G., &Sheets, V. (2002). A comparison of methods to test mediation and other intervening variable effects.Psychological Methods,7, 83–104.
MacKinnon, D. P., Lockwood, C. M., &Williams, J. (2004). Confidence limits for the indirect effect: Distribution of the product and resampling methods.Multivariate Behavioral Research,39, 99–128.
MacKinnon, D. P., Taborga, M. P., &Morgan-Lopez, A. (2002). Mediation designs for tobacco prevention research.Drug & Alcohol Dependence,68 (Suppl. 1), S69-S83.
MacKinnon, D. P., Warsi, G., &Dwyer, J. H. (1995). A simulation study of mediated effect measures.Multivariate Behavioral Research,30, 41–62.
Meeker, W. Q., Jr.,Cornwell, L. W., &Aroian, L. A. (1981).The product of two normally distributed random variables (Selected Tables in Mathematical Statistics, Vol. 7). Providence, RI: American Mathematical Society.
Morgan-Lopez, A. A., Castro, F. G., Chassin, L., &MacKinnon, D. P. (2003). A mediated moderation model of cigarette use among Mexican American youth.Addictive Behaviors,28, 583–589.
Oetting, E. R., Donnermeyer, J. F., Trimble, J. E., &Beauvais, F. (1998). Primary socialization theory: Culture, ethnicity, and cultural identification. The links between culture and substance use: IV.Substance Use & Misuse,33, 2075–2107.
SAS Institute (2000). SAS (Version 8e) [Computer software]. Cary, NC: Author.
Sharma, S., Durand, R. M., &Gur-Arie, O. (1981). Identification and analysis of moderator variables.Journal of Marketing Research,18, 291–300.
Simon, H. A. (1954). Spurious correlation: A causal interpretation.Journal of the American Statistical Association,49, 467–479.
Sobel, M. E. (1982). Asymptotic confidence intervals for indirect effects in structural equation models. In S. Leinhardt (Ed.),Sociological methodology (pp. 290–313). San Francisco: Jossey-Bass.
Tein, J.-Y., Sandler, I. N., MacKinnon, D. P., &Wolchik, S. A. (2004). How did it work? Who did it work for? Mediation in the context of a moderated prevention effect for children of divorce.Journal of Consulting & Clinical Psychology,72, 617–624.
Tein, J.-Y., Sandler, I. N., &Zautra, A. J. (2000). Stressful life events, psychological distress, coping, and parenting of divorced mothers: A longitudinal study.Journal of Family Psychology,14, 27–41.
Unger, J. B., Cruz, T. B., Rohrbach, L. A., Ribisl, K. M., Baezconde-Garbanti, L., Chen, X., et al. (2000). English language use as a risk factor for smoking initiation among Hispanic and Asian American adolescents: Evidence for mediation by tobacco-related beliefs and social norms.Health Psychology,19, 403–410.
West, S. G., &Aiken, L. S. (1997). Toward understanding individual effects in multicomponent prevention programs: Design and analysis strategies. In K. J. Bryant, M. Windle, & S. G. West (Eds.),The science of prevention: Methodological advances from alcohol and substance abuse research (pp. 167–209). Washington, DC: American Psychological Association.
Wolchik, S. A., West, S. G., Westover, S., Sandler, I. N., Martin, A., Lustig, J., et al. (1993). The children of divorce parenting intervention: Outcome evaluation of an empirically based program.American Journal of Community Psychology,21, 293–331.
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This research was supported by NIMH Grant 2T32MH18387, NIDA Grant 5R01DA09757-04, and the Center for Interdisciplinary Substance Abuse Research, RTI International. We acknowledge the contributions of Matthew Fritz, Chondra Lockwood, Aaron Taylor, and Stephen G. West to this work. Portions of this research were presented at the 9th annual meeting of the Society for Prevention Research, June 2001, Washington, DC.
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Morgan-Lopez, A.A., Mackinnon, D.P. Demonstration and evaluation of a method for assessing mediated moderation. Behavior Research Methods 38, 77–87 (2006). https://doi.org/10.3758/BF03192752
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DOI: https://doi.org/10.3758/BF03192752