Another limitation comes from the fact that, because of the correlational nature of the present study, we cannot determine causality from any of the risk or protective factors that we examined. Nevertheless, the risk factors were chosen because of their theoretical importance for the development of behavior problems. Additionally, there is an elevated likelihood of type II error because of shared variance between the risk factors. In other words, we may have failed to detect meaningful associations because of overlapping variance and conservative cutoffs. There is an increase in power to detect associations in studies with repeated measures, however, providing further confidence in our findings (Muthén & Curran, 1997). Finally, we did not consider how risk factors may interact to influence externalizing problems. Emerging findings suggest, for example, that temperament-by-parenting interactions augment the prediction of children’s externalizing behavior (Bates & Pettit, in press; Bates, Schermerhorn, & Petersen, 2012). Thus, future studies could extend these findings by testing the interactions among risk factors. Future studies might also consider the effects that risk factors may have on each other in successive developmental
