IN SELECTING A PARTICULAR MEASUREMENT TOOL, EVALUATORS SHOULD CONSIDER THREE DIFFERENT OPTIONS: USING ONE OR MORE OF THE AVAILABLE MEASURING TOOLS, CONSTRUCTING A NEW RATING SCALE, OR MEASURING THE ATTAINMENT OF INDIVIDUAL CLIENT GOALS. SOURCES OF INFORMATION FOR MEASURING INDIVIDUAL GOAL ATTAINMENT INCLUDE CLIENTS, CLINICIANS, AND INFORMANTS. ONE ADVANTAGE TO USING A STANDARD MEASURING INSTRUMENT IS THE INFORMATION AVAILABLE ABOUT PSYCHOMETRIC PROPERTIES THE INSTRUMENT HAS EXHIBITED IN PREVIOUS STUDIES. ORGANIZING AN EFFICIENT OUTCOME ASSESSMENT REQUIRES THE ESTABLISHMENT OF WHO IS TO PERFORM RATINGS AND THE COST OF THE SCALE FORMAT AND COMPUTER INPUT. USEFUL MEASUREMENT APPROACHES INVOLVE GENERAL-PURPOSE SCALES, SPECIAL-PURPOSE INSTRUMENTS, AND CLASSIFICATION INSTRUMENTS. EACH OF THESE APPROACHES IS DESCRIBED. REFERENCES ARE INCLUDED. APPENDIXES CONTAIN INFORMATION ON A CLINICAL DRUG UNIT EVALUATION PROGRAM AND NUMEROUS EVALUATION SCALES, INSTRUMENTS, AND FORMS. (DEP)