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To install with SPSS 28, you can Download download the current package from the Hayes Process macro web site for all the gory details, but if you are already familiar with it. or download the file attached to this page.
To install, start SPSS 28 and in the “Extensions” menu, choose “Utilities”, then “Custom Dialog Builder”, then browse to where you saved the process.spd file and once installed, you should then be able to run it from under the Analyze/Regression menu.
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