Missing data
We will model missing responses/covariates in our longitudinal models. We will consider missing data mechanisms, including missing completely at random, missing at random, or missing not at random, to handle missing data due to a missed assessment time point, study dropout, or unusable MRIs. The full information maximum likelihood estimation (FIML) method will be used in fitting statistical models including LMM and LVM, which allow incomplete data (i.e., cases with missing data will contribute to the analysis).