Rapport et al. (1999) found previously that disruptive behavior problems are unrelated to academic underachievement later in life, except by their common relation with attention deficits. Alternatively, it may be that methodological issues may account for some ofืthese differences. Whereas our variables of interest (on-task behaviors) were directly observed by the investigators, ratings for ODD problems and academic performance were based on teacher's evaluations on the first observation day, possibly including a perception bias or referring to a different time frame. Here we have no long-term outcome data on children's academic achievement.