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 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. Note to Widows Vista:
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 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.