ADVOCATES OF INSERVICE TRAINING ARGUE THAT SUCH PROGRAMS ENHANCE THE PROFESSIONALISM AND EFFECTIVENESS OF YOUTH WORKERS. HOWEVER, A NUMBER OF FACTORS SUGGEST THAT SUCH TRAINING HAS ONLY MINISCULE EFFECTS ON YOUTH WORKERS COMPARED TO DAY-TO-DAY, ON-THE-JOB EXPERIENCES. EXPERIMENTAL AND CONTROL GROUPS EACH ATTENDED ONE OF TWO CONSECUTIVE 12-WEEK TRAINING SESSIONS. THE SESSIONS COVERED A BROAD RANGE OF TOPICS INCLUDING YOUTH PROBLEMS, BEHAVIORAL MODIFICATION, INDIVIDUAL COUNSELING, GROUP COUNSELING, AND EMPLOYMENT TRAINING OPPORTUNITIES. AT THE END OF THE FIRST SESSION A SINGLE MEASUREMENT WAS TAKEN OF BOTH THE EXPERIMENTAL AND CONTROL GROUPS USING A RANDOMIZED POSTEST-ONLY CONTROL GROUP DESIGN METHOD, TESTING HYPOTHESES AS TO THE EFFECTS OF THE TRAINING IN TERMS OF THE YOUTH WORKERS' TECHNIQUES AND THEIR INTERACTIONS WITH THEIR CLIENTS, AND CLIENTS' PARENTS AND FRIENDS. RESULTS FROM A 120-ITEM QUESTIONNAIRE SUPPORTED FIVE OF EIGHT HYPOTHESES COMPARING TRAINEES WITH CONTROLS IN TERMS OF TECHNIQUES SUCH AS REINFORCEMENT AND CERTAIN ATTRIBUTES OF INTERPERSONAL RELATIONS WITH CLIENTS AS WELL AS THEIR PARENTS AND FRIENDS. SHORTCOMINGS IN THE CONTENT OF THE TRAINING PROGRAM APPEAR RESPONSIBLE FOR INCONCLUSIVE RESULTS AND LACK OF VERIFICATION ON SEVERAL OF THE HYPOTHESES. BEHAVIOR CHANGES ARE MOST EVIDENT WHEN THE DESIRED BEHAVIOR BEING ADVOCATED IN THE TRAINING SESSION DOES NOT CONFLICT WITH THE WORKERS' ON-THE-JOB EXPERIENCES. ADDITIONAL RESEARCH IS NEEDED INTO THE EFFECTS OF IN-HOUSE TRAINING. A STATISTICAL TABLE, FOOTNOTES, AND REFERENCES ARE PROVIDED. (KCP)