Utilities for Probing Interactions

Over the past several years Dan Bauer, Kris Preacher, Mike Willoughby, and I have worked on a number of projects related to testing, probing, and plotting interactions in multiple linear regression, multilevel regression, and latent curve modeling. We've written a few papers, and these are listed below. We've also developed a number of online calculators that compute simple intercepts, simple slopes, and regions of significance. These calculators also generate publication-ready plots for simple intercepts and slopes, and regions of significance.

We have re-located all of the materials for our online interaction calculators to a new server. Please visit

http://http://quantpsy.org/interact/index.html

to access these calculators and the associated support material.

Below are the related papers:

Bauer, D.J., & Curran, P.J. (2005). Probing interactions in fixed and multilevel regression: Inferential and graphical techniques. Multivariate Behavioral Research, 40, 373-400.

Curran, P.J., Bauer, D.J., & Willoughby, M.T. (2004). Testing and probing main effects and interactions in latent curve analysis. Psychological Methods, 9, 220-237.

Curran, P.J., Bauer, D.J, & Willoughby, M.T. (2006). Testing and probing interactions in hierarchical linear growth models. In C.S. Bergeman & S.M. Boker (Eds.), The Notre Dame Series on Quantitative Methodology, Volume 1: Methodological Issues in Aging Research, (pp.99-129). Mahwah, NJ: Lawrence Erlbaum Associates.

Preacher, K.J., Curran, P.J., & Bauer, D.J. (2006). Computational tools for probing interactions in multiple linear regression, multilevel modeling, and latent curve analysis. Journal of Educational and Behavioral Statistics, 31, 437-448.