partial vs semi-partial correlations in MR

Posted by wsu_wright on Oct 22, 2006; 4:24pm
URL: http://spssx-discussion.165.s1.nabble.com/partial-vs-semi-partial-correlations-in-MR-tp1071617.html

Just when I get this figured out I read more & get confused.  Partial vs semi-partial correlations in multiple regsression-- which is the better measure squared to identify the unique contribution to the explained variance in the DV?

In Tabachnick & Fidell (2007, 5th ed, pp145-146) they note the "squared semi-partial correlations expresses the unique contribution of the IV to the total variance of the DV."  Whereas Norusis (spss 14 statistical procedures companion,  p248) states "The square of the partial correlation coefficient tells you waht proportion of the unexplained variance in the DV is explained..."