This study examined the content validity of a juvenile psychopathy measure, the Childhood Psychopathy Scale (CPS; D. R. Lynam, 1997), based on a downward translation of an adult instrument, the Hare Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991). The CPS was compared with two other indices of juvenile psychopathy: (a) an index derived from expert ratings and (b) an empirical index based on correlations with adult psychopathy. The 100 items of the Common Language Q-Sort (CLQ; A. Caspi et al., 1992) provided a common metric for the comparison. Psychopathy and personality were assessed at age 13 years with the mother-reported CPS and the CLQ. Psychopathy was assessed at age 24 years with the interviewer-rated Psychopathy Checklist: Screening Version (PCL:SV; S. D. Hart, D. N. Cox, & R. D. Hare, 1995). Data from over 250 participants of the middle sample of the Pittsburgh Youth Study were used to examine these relations. Item content analyses demonstrated considerable overlap among the three indices, indicating that the downward translation utilizes criteria similar to those of experts and the empirically-derived measure. In addition, these indices, even after removing overlapping items, demonstrated considerable convergence, also supporting the content validity of the downward translation. These results suggest that the downward translation method is adequate for understanding the juvenile psychopathy construct.