Two 9- to 10-month-long studies (N = 137) examined the interaction between parenting stress and behavior problems in children with autistic spectrum disorders (ASDs). Study 1 focused on very young children, and Study 2 employed a wider range of child ages; both studies assessed these factors at 2 points in time. The researchers noted a strong association between parenting stress and child behavior problems when they controlled for other factors, such as ASD severity and intellectual functioning (Study 1 and 2). However, Study 1 indicated that when the children were very young (2:6–4:0 years), ASD severity related most strongly to parenting stress. In addition, both Study 1 and Study 2 indicated that parenting stress at Time 1 was a stronger predictor of child behavior problems at Time 2, rather than vice versa.