Phase I of the study, which was conducted from 1997 to 2002, collected data that compared youths and adults regarding their capacities as trial defendants. The study involved more than 900 youths and more than 450 adults. Phase II of the study consists of developing tools to assist courts and mental health professionals in evaluating a youth's competence to stand trial. Study findings indicate that approximately one-third of 11- to-13-year-olds and one-fifth of 14- to 15-year-olds probably were not competent to stand trial. Compared to young adults many of these youth lacked an essential knowledge of the judicial process. Many of the younger children were unable to draw on relevant facts and produce logical conclusions. They were also less able than adults to conceive of the future consequences of their decisions. Thirty percent of children 11- to 13-years-old, and 19 percent of those ages 14 and 15 performed at the level of mentally ill adults who have been found incompetent to stand trial. The study also found that adolescent immaturity may affect the behavior of the youth as defendants in ways that extend beyond competence to stand trial; as a group, they were more willing than adults to confess rather than remain silent when confronted by an authority figure, especially if they believed it would result in an immediate reward, such as going home. For similar reasons, they may be more willing to accept a prosecutor's plea agreement. These age-related findings held true regardless of gender and ethnicity and across geographic and socioeconomic boundaries. The findings were also consistent regardless of the youth's previous contact with the legal system. Adolescents with below-average intelligence were most likely to lack the abilities related to competence. Below average intelligence characterizes a disproportionately large number of youth in the juvenile justice system. These findings show the importance of expanding the way the justice system views juveniles' competence to stand trial. The next issue to be addressed in this study is the development of effective tools and procedures for assessing adolescents' competence.