Basics: Highway to the Danger Zone: Why median-splitting your continuous data can ruin your results.

Not too long ago, I wrote an article here about advanced procedures for examining interactions in multiple regression. As I described some of the challenges researchers commonly face in trying to examine differences between people in a data set, I argued that when it comes to data analysis, splitting a continuous variable into a dichotomy (i.e. two categories) is kind of a dumb idea (MacCallum et al, 2002). Continue reading

Data management with SPSS + MS Excel

Like many others, I have historically used SPSS as my go-to data management program. Many of those with whom I work do the same, and with good reason. It’s flexible and fairly easy to use for basic data management tasks (and let’s be honest, most people are trained in SPSS during their initiation into data analysis in psychology). One life changing moment for many users of SPSS is the day that one realizes the utility of the syntax window vis a vis the point and click interface. This becomes more apparent during the data management phase than perhaps at any other point. This article assumes that you’re already past this point of no return.

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