Improvement in externalizing problems, compared with stable low levels of externalizing problems, was not predicted by T3 EC or impulsivity when T1 levels of these characteristics were controlled (there were some near significant findings). To determine whether this pattern was due to controlling for T1 levels of variables, we conducted supplemental analyses in which pattern of change in maladjustment was related to T3 EC or impulsivity without controlling for T1 levels of the latter variables. We found that consistently low versus improving externalizing status was related to higher attentional EC (in two of four analyses, with one more being near significant) and inhibitory control (all four analyses) and lower impulsivity (two of four analyses, with one more being near significant) at T3. We also ascertained that SL versus IM externalizing status was consistently related to high EC (all but one contrast was significant) and low impulsivity (all contrasts were significant) at T1. Thus, improving in comparison to stable control status was still predicted by low regulation and high impulsivity at T3, but when the two groups’ starting point at T1 was taken into account, they apparently moved as much in a positive direction.
