Mean centering helps alleviate “micro” but not “macro” multicollinearity

Dawn Iacobucci1, Matthew J. Schneider2, Deidre L. Popovich3, Georgios A. Bakamitsos4
1Vanderbilt University, Nashville, USA
2Northwestern University, Evanston, USA
3Texas Tech University, Lubbock, USA
4Stetson University, DeLand, USA

Tóm tắt

There seems to be confusion among researchers regarding whether it is good practice to center variables at their means prior to calculating a product term to estimate an interaction in a multiple regression model. Many researchers use mean centered variables because they believe it’s the thing to do or because reviewers ask them to, without quite understanding why. Adding to the confusion is the fact that there is also a perspective in the literature that mean centering does not reduce multicollinearity. In this article, we clarify the issues and reconcile the discrepancy. We distinguish between “micro” and “macro” definitions of multicollinearity and show how both sides of such a debate can be correct. To do so, we use proofs, an illustrative dataset, and a Monte Carlo simulation to show the precise effects of mean centering on both individual correlation coefficients as well as overall model indices. We hope to contribute to the literature by clarifying the issues, reconciling the two perspectives, and quelling the current confusion regarding whether and how mean centering can be a useful practice.

Từ khóa


Tài liệu tham khảo

Aiken, L. S., & West, S. G. (1991). Multiple regression: Testing and interpreting interactions. Newbury Park: Sage.

Allison, P. D. (1977). Testing for interaction in multiple regression. American Journal of Sociology, 83(1), 144–153.

Arnold, H. J., & Evans, M. G. (1979). Testing multiplicative models does not require ratio scales. Organizational Behavior and Human Performance, 24, 41–59.

Bohrnstedt, G. W., & Goldberger, A. S. (1969). On the exact covariance of products of random variables. Journal of the American Statistical Association, 64(328), 1439–1442.

Bradley, R. A., & Srivastava, S. S. (1979). Correlation in polynomial regression. The American Statistician, 33(1), 11–14.

Dalal, D. K., & Zickar, M. J. (2012). Some common myths about centering predictor variables in moderated multiple regression and polynomial regression. Organizational Research Methods, 15(3), 339–362.

Dunlap, W. P., & Kemery, E. R. (1987). Failure to detect moderating effects: Is multicollinearity the problem? Psychological Bulletin, 102(3), 418–420.

Echambadi, R., & Hess, J. D. (2007). Mean centering does not alleviate collinearity problems in moderated multiple regression models. Marketing Science, 26(3), 438–445.

Friedrich, R. J. (1982). In defense of multiplicative terms in multiple regression equations. American Journal of Political Science, 26(4), 797–833.

Goodman, L. A. (1960). On the exact variance of products. Journal of the American Statistical Association, 55(292), 708–713.

Irwin, J. R., & McClelland, G. H. (2001). Misleading heuristics and moderated multiple regression models. Journal of Marketing Research, 38(February), 100–109.

Jaccard, J., Wan, C. K., & Turrisi, R. (1990). The detection and interpretation of interaction effects between continuous variables in multiple regression. Multivariate Behavioral Research, 25(4), 467–478.

Kromrey, J. D., & Foster-Johnson, L. (1998). Mean centering in moderated multiple regression: Much ado about nothing. Educational and Psychological Measurement, 58(1), 42–67.

Marquardt, D. W. (1970). Generalized inverses, ridge regression, biased linear estimation, and nonlinear estimation. Technometrics, 12(3), 591–612.

Marquardt, D. W. (1980). You should standardize the predictor variables in your regression models. Journal of the American Statistical Association, 75(369), 87–91.

Shieh, G. (2009). Detecting interaction effects in moderated multiple regression with continuous variables: Power and sample size considerations. Organizational Research Methods, 12(3), 510–528.

Shieh, G. (2010). On the misperception of multicollinearity in detection of moderating effects: Multicollinearity is not always detrimental. Multivariate Behavioral Research, 45(3), 483–507.

Shieh, G. (2011). Clarifying the role of mean centring in multicollinearity of interaction effects. British Journal of Mathematical and Statistical Psychology, 64, 462–477.

Smith, K. W., & Sasaki, M. S. (1979). Decreasing multicollinearity: A method for models with multiplicative functions. Sociological Methods & Research, 8(1), 35–56.

Stone, E. F., & Hollenbeck, J. R. (1984). Some issues associated with the use of moderated regression. Organizational Behavior and Human Performance, 34, 195–213.