This study evaluated the Five P's (Parent/Professional Preschool Performance Profile) observational scale through which preschool teachers and parents evaluate the behavior of disabled or nondisabled children in natural settings while the children interact with familiar adults over prolonged periods of time. Developmental skills and interfering behaviors are the two main categories observed and rated. In this replication study 370 children ranging in age from 20 months to 7 years from a wide range of geographical areas were assessed for teacher/parent rating agreement, Cronbach Alpha reliability, test retest reliability, and the development of a set of experimental norms for the five major subscales. Involved teachers and parents rated the scales positively and the replication study presented strong supportive evidence that these ratings met professional standards of reliability for teachers. (PB)