Macros {taken from Jason Newsom's site, http://www.upa.pdx.edu/IOA/newsom/macros.htm}
 
Disclaimer:  These macros have been tested by myself and by others.  However, I urge to calculate at least one set of simple slopes by hand to make sure the macro computes the simple slopes correctly.  The macros have been developed for SPSS Windows and may not perform correctly with SPSS for Macintosh. 

 

Right click to download.

 
Simple1.sps (SPSS for Windows only, works for all versions through Version 13) SPSS macro for testing the interaction between two continuous variables and calculating simple slopes.  This macro can be accessed with two simple lines in any syntax file.   It centers two predictors for a two-way interaction, computes the product term, runs a regression analysis to test the interaction, calculates the correct standardized coefficient for the interaction, calculates simple slopes at –1 SD, the mean, and +1SD, tests them for significance, and plots them.  Download the SPSS syntax file containing the macro and store it on your hard drive.  Instructions on how to use it are contained in a comment box at the beginning of the macro.  Two lines of syntax are needed to call the macro and execute it. 

 
Simple2.sps. (SPSS for Windows only, works for all versions through Version 13) An SPSS macro for testing the  interaction between a continuous and a dichotomous variable and calculating simple slopes.  This macro can be accessed with two simple lines in any syntax file.   It centers the continuous predictor for a two-way interaction, computes the product term, runs a regression analysis to test the interaction, calculates the correct standardized coefficient for the interaction, calculates simple slopes at 0 and 1 of the moderator, tests them for significance, plots them, and calculates DeShon and Alexander’s homogeneity ratio.  Download the SPSS syntax file containing the macro and store it on your hard drive.  Instructions on how to use it are contained in a comment box at the beginning of the macro.  Two lines of syntax are needed to call the macro and execute it.