We hypothesized that hyperactivity defines the first stage and that antisocial problems define a second stage in a progression that leads eventually to early-onset delinquency. As expected, a structural equation model (SEM) showed that a latent construct for hyperactivity was significantly related to a latent construct for antisocial problems. We hypothesized that this path reflected a shared mechanism, disrupted parental discipline. A second SEM showed that the relation between hyperactivity and antisocial behavior really reflected a shared disruption in parental discipline. A third SEM showed that having antisocial parents was uniquely correlated with antisocial children but not with hyperactivity. A fourth SEM showed that early-onset delinquency was predicted by a latent construct for antisocial child; but when this was partialed out, the contribution for hyperactivity was nonsignificant.