Macros
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 17) 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. Note to Widows Vista
users: You may experience problems
with this (or any) macro because you do not have permission to write to a
location on the hard drive. Defaults in Windows Vista may restrict saving to
the C: drive as this macro requires, and you may need to grant permission to
yourself by disabling
this protection altogether or granting
permission to save to your own C: drive. Note to
PSU lab users. PSU lab users should download the H: version of the
macro, which saves to a location that usually is not protected on lab
computers.
Simple2.sps. (SPSS for Windows only, works for all versions through
Version 17) 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.