There is a growing consensus that major dimensions of early child problem behaviors can be distinguished, and that problem behaviors develop in an orderly sequence over time. There is also a body of longitudinal data on the continuity of problem behaviors over time. It is less well known whether some problem behaviors may serve as catalysts, in that their presence leads to worsening behavior, while their absence facilitates improvement. It also remains to be seen which classification scheme of child problem behaviors has the highest predictive yield in forecasting long-term outcomes. Least explored are dynamic classifications or pathways, in which youth are classified according to their history and sequence of problem behaviors as those behaviors unfold over time. Relatively little is known about the diversification of problem behavior over time, but it is more certain that diversification is inversely related to cessation. Figures, references