The Childhood Psychopathy Scale is a 41-item checklist of psychopathic traits in children. It is intended to be completed by parents of children in the pre-adolescent and adolescent years. It assesses interpersonal, affective, and behavioral components of psychopathic personality. Most research concerning the validity of the CPS has been done on youth referred to community treatment centers, not on institutionalized young offenders.
Lynam, Donald R. (1997). Pursuing the psychopath: Capturing the fledgling psychopath in a nomological net. Journal of Abnormal Psychology, Vol 106(3), 425-438. doi: 10.1037/0021-843X.106.3.42