A psychiatric instrument, the Clinical Assessment Inventory, is an integral part of a comprehensive hospital treatment program for adults based upon behavioral technology ( 2 ) . The inventory was designed to provide a daily, quantitative, behavioral assessment of patients' progress when completed twice daily by nursing staff, once by the day shift and once by the evening shift. Each patient is observed during regularly scheduled nursing rounds and rated as to presence or absence of 50 sub-categories of behavior, yielding a total score range for the entire day of 0 to 100 points. Major categories are general appearance, orientation, inferred mood, speech form, speech content, social interaction, room maintenance, program cooperation, program participation, and global rating. The total score determines to which of three levels of therapeutic activities and privileges the patient will be assigned the day following. Daily staff review of the individual items pinpoints specific behaviors to be targeted clinically for individually tailored, treatment planning. Independent observations and ratings of 10 patients in a private, acute, psychiatric hospital were made by pairs of nursing staff during day and evening shifts for five successive weekdays. Average percentage agreement for the day shift was 88.4 and for the evening shift was 88.6. Average reliabiliry for the day shift was .852 and for the evening shift was .853. The correlation between scores on Day 2 and Day 3 of hospitalization for 100 patients was .945. Observer reliability and stability of total scores are adequate for this inventory to be used as a clinical and a research instrument. As a preliminary external test of validity, patients were administered the Short Clinical Rating Scale ( 1 ) on the day prior to discharge from the hospital. Correlation with Clinical Assessment Inventory scores on char day was ,774 ( p > .001, df = 98) . The rating scale has primarily been utilized in research to assess patients' progress through observation by nursing staff; whereas, the inventory is designed primarily as an integrated programmatic instrument. Preliminary assessment of validity and reliability indicates potential for use in research with acute, adult psychiatric patients.