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
and PSU lab 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. PSU lab users should download the C:\temp version of the
macro, which saves to a folder 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.