The Client Observation Checklist (COC) was developed to evaluate Project ADAPT's intervention in three behavioral areas: bathing; dressing; and socialization. Project ADAPT is designed to provide services to meet the needs of chronically mentally ill residents of nursing homes. Specifically, the project provides staff trained to work with the mentally handicapped and therapeutic intervention to raise motivation levels. Fifteen clients of Project ADAPT at each of two facilities were selected for observation. Observations were made during the last 2 weeks of March 1984, before Project ADAPT had begun at either location. Two pairs of independent raters averaged 94.44% and 95.37% agreement, respectively, establishing very high reliability for the COC. The validity of the COC was determined by correlating subscale totals with case manager ratings on the Treatment Setting Determination Survey. Despite two sources of potential error variance, intercorrelations between bathing and dressing subscales/items all exceeded 0.70, establishing the validity of the COC. The COC required an average of 19.67 minutes to administer. The non-significant tendency for clients at one facility to have a higher level of functioning is described as consistent with the nonequivalent control group design used for evaluation. Two data tables and the COC are included. (TJH)