NCJ Number
63806
Journal
Sociological Methods and Research Volume: 8 Issue: 1 Dated: (AUGUST 1979) Pages: 35-56
Date Published
1979
Length
22 pages
Annotation
THIS SOCIOLOGICAL RESEARCH ARTICLE DESCRIBES A METHOD FOR DECREASING MULTICOLLINEARITY AMONG INDEPENDENT VARIABLES FOR MODELS WITH MULTIPLICATIVE FUNCTIONS.
Abstract
THE PROBLEMS CREATED BY MULTICOLLINEARITY AMONG THE INDEPENDENT VARIABLES IN LEAST-SQUARES REGRESSION ARE WELL-KNOWN. HOWEVER, WHEN THE MULTICOLLINEARITY AMONG THE INDEPENDENT VARIABLES IN A REGRESSION MODEL IS DUE TO A HIGH CORRELATION OF A MULTIPLICATIVE FUNCTION WITH ITS CONSTITUENT VARIABLES, THE MULTICOLLINEARITY CAN BE GREATLY REDUCED BY CENTERING THESE VARIABLES AROUND MINIMIZING CONSTANTS BEFORE FORMING THE MULTIPLICATIVE FUNCTION. THE VALUES OF THESE CONSTANTS THAT MINIMIZE THE MULTICOLLINEARITY ARE DERIVED, AND THE CONDITIONS ARE IDENTIFIED UNDER WHICH CENTERING THE VARIABLES ABOUT THEIR MEANS WILL REDUCE THE MULTICOLLINEARITY. AMONG THE ADVANTAGES OF THIS PROCEDURE ARE THAT THE MEAN SQUARE ERROR REMAINS AT ITS MINIMUM, THAT THE COEFFICIENTS FOR OTHER VARIABLES IN THE MODEL ARE UNAFFECTED BY IT, AND THAT THE ORDINARY LEAST-SQUARES ESTIMATES FOR THE ORIGINAL MODEL CAN BE CALCULATED FROM THOSE FOR THE MODIFIED MODEL. THUS, EVEN WHEN ESTIMATES OF THE ORIGINAL MODEL ARE DESIRED, THE PROCEDURE CAN BE USED TO REDUCE NUMERICAL ERROR. TABULAR DATA, NOTES, AND REFERENCES ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED--MJW)