PRINCIPAL ISSUES IN EVALUATION ARE SUMMARIZED AS THOSE REGARDING THE SEVERAL DEFINITIONS OF EVALUATION, THE MANY MOTIVES AND PURPOSES OF INDIVIDUALS INVOLVED IN EVALUATION, THE VARIETY OF PROGRAMS, THE RANGE OF OF EVALUATION DESIGNS AND DATA COLLECTION STRATEGIES, AND THE MANY MEASURES TO BE CONSIDERED. MOTIVATION IS IMPORTANT SINCE ATTITUDES, FEELINGS, AND PRESSURES HAVE THEIR IMPACT ON THE NATURE AND QUANTITY OF INFORMATION GATHERED, ASSEMBLED, AND DISSEMINATED. PURPOSES FOR COLLECTING INFORMATION ABOUT PROGRAMS INCLUDE ROUTINE REPORTING, MANAGEMENT GUIDANCE, RESEARCH, AND OUTCOME EVALUATION. EVALUATION OBJECTIVES REGARDING PROGRAMS FOCUS ON PROGRAM THEORIES AND PRINCIPLES, THE EXTENT OF PROGRAMS, PROGRAM INTENSITY, AND THE DESCRIPTION OF PROGRAM CONTENT. MEASURES OF ACCOMPLISHMENT IN THE FIELDS OF ALCOHOLISM, DRUG ABUSE, AND MENTAL HEALTH TREATMENT PROGRAMS ARE OF TWO KINDS: (1) SOCIAL INDICATORS GENERALLY TIED TO LOCALES AND NOT NECESSARILY INVOLVING PATIENTS OR CLIENTS WHO HAVE RECEIVED TREATMENT OR OTHER SERVICES; AND (2) INDIVIDUAL MEASURES OBTAINED FROM OR ABOUT PERSONS FOR WHOM A TREATMENT PROGRAM WAS DESIGNED AND SOMETIMES INCLUDING THE EFFECT OF TREATMENT OR RELATED PERSONS SUCH AS FAMILIES. ELEMENTS IN EVALUATIVE RESEARCH DESIGNS COVER THE MANNER IN WHICH PATIENTS OR CLIENTS ARE CHOSEN FOR INCLUSION IN A STUDY, THE POINT OR POINTS IN TIME AT WHICH MEASUREMENT IS MADE, AND THE USE OF COMPARISON GROUPS. THE EVALUATION OF PROGRAMS UNDER THE AUSPICES OF THE ALCOHOL, DRUG ABUSE, AND MENTAL HEALTH ADMINISTRATION (ADAMHA) IS CONSIDERED. NOTES AND A BIBLIOGRAPHY ARE PROVIDED. SELECTED OUTCOME MEASURES IN EVALUATION FOR ALCOHOL ABUSE, DRUG ABUSE, AND MENTAL HEALTH INTERVENTIONS ARE LISTED IN AN APPENDIX. FOR A SCHEMATIC PRESENTATION OF 25 WORKS LISTED IN THIS ARTICLE, SEE NCJ-51613. (DEP)