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Variable vs. Participant-wise Standardization

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To make sense of their data and effects, psychologists often standardize (Z-score) their variables. However, in repeated-measures designs, there are three ways of standardizing data: Variable-wise: The most common method. A simple scaling and reducing of each variable by their mean and SD. Participant-wise: Variables are standardized “within” each participant, i.e., for each participant, by the participant’s mean and SD. Full: Participant-wise first and then re-standardizing variable-wise. Unfortunately, the method used is often not explicitly stated. This is an issue as these methods can generate important discrepancies that contribute to the reproducibility crisis of psychological science. In the following, we will see how to perform those methods and look for differences. We will take a dataset in which participants were exposed to negative pictures and had to rate their emotions (valence) and the amount of memories associated with the picture…
Original Post: Variable vs. Participant-wise Standardization