The model indicates that impulsivity mediates the effects of age and ECF on both risk and problem behavior. We further tested the possibility that impulsivity explains both risk taking and externalizing problems by restricting the path from problems to risk taking to zero. This produced only a slightly less adequate fit to the data, χ2 (1) = 1.11, p > .15. Hence, there was support for only one path leading to risk taking in this sample of preadolescents. Furthermore, the model accounted for nearly 70% of the variation in the risk behavior factor and slightly over 50% of the variation in problem behaviors. This indicates that impulsivity can account for a large share of the variation in both of these outcomes. Nevertheless, the amount of variation explained by ECFs, age, and gender was quite small (about 8%). This indicates that impulsivity was largely influenced by factors outside the model.
