The interRAI ChYMH-DD is intended to be used with children and youth with developmental disabilities in mental health settings to support comprehensive care planning, outcome measurement, quality indicators, and case mix classification to estimate relative resource intensity. It employs specific observation periods in order to provide reliable and valid measures of clinical characteristics that reflect the child's or youth's strengths, preferences, and needs. In keeping with other interRAI instruments, the basic time frame for assessment was set at 3 days unless otherwise indicated. Triggers for numerous Collaborative Action Plans to support care planning decisions are also embedded in the instrument. There are two versions of the ChYMH-DD assessment form. Typically, the In-patient form would be used for a child or youth who currently resides in a residential facility or psychiatric facility/unit, and the Community-Based form for a child or youth who resides in a community setting.