This program estimates the percentage of the total effect that is mediated and the ratio of the indirect to the direct effect by using the Sobel test, written by William Dudley PhD and Jose Benuzillo MA, University of Utah College of Nursing, 2/11/04. We thank the authors of this program very kindly for sharing it with us and for allowing us to post it on our site.
You can download a word document explaining their program here .
Here is an example SPSS syntax file and example SPSS data file for running their program.