Longitudinal studies are necessary to examine individual change over time, with group status often being an important variable in explaining some individual differences in change. Although sample size planning for longitudinal studies has focused on statistical power, recent calls for effect sizes and their corresponding confidence intervals…

We are grateful to the commentators for providing many stimulating and valuable observations. The main point of our article was to call attention to the overestimation of individual differences correlations in a subset of neuroimaging papers. To structure our discussion of these comments, we list the main points from our paper, note where…