Sustained attention is an important cognitive process that affects various other aspects of cognition. A common focus for the study of sustained attention is attention-deficit hyperactivity disorder among children. The Adolescent Brain Cognitive Development (ABCD) Study provides ADHD symptomology scores from the Child Behavior Checklist, as well as rest and n-back task fMRI data from children between the ages of 9 and 13. In the current study, a preexisting connectome-based predictive modeling (CPM) protocol is used to predict sustained attention abilities and changes in those abilities over a three-year time span. Additionally, a new predictive model is created to judge whether a protocol based on child brain data is more effective at estimating sustained attention scores that one trained on adult data. The attempt at applying a “publication-preregistered” model and developing a new one opens up a host of outstanding questions. Future longitudinal efforts of the ABCD study would afford more opportunities to study sustained attention with functional connectivity.