THE EVALUATION WAS CONDUCTED AT 1- AND 3-MONTH POST-HOSPITALIZATION INTERVALS AND THEREFORE PROVIDED INFORMATION ON QUESTIONNAIRE RETURN RATES OBTAINED ON MULTIPLE OCCASIONS OVER AN EXTENDED PERIOD OF TIME. THE SUBJECTS WERE 39 PSYCHIATRIC PATIENTS PREDOMINANTLY LOWER SOCIAL ECONOMIC STATUS ADULTS (17 FEMALES AND 22 MALES WITH A MEAN AGE OF 25.8 YEARS), WHO WERE DISCHARGED FROM A GENERAL PSYCHIATRIC TREATMENT PROGRAM OVER AN 18-WEEK PERIOD. ADDITIONAL SUBJECTS WERE 39 INDIVIDUALS WHO WERE DESIGNATED AS 'SIGNIFICANT OTHERS' BY PATIENTS. ALL PATIENTS WERE MAILED AN 83-ITEM VERSION OF THE PROFILE OF ADAPTION TO LIFE SCALE AND A COVER LETTER THAT SOLICITED COOPERATION WITH THE FOLLOWUP PROCEDURE. SIGNIFICANT OTHERS WERE MAILED A 71-ITEM REVISED COPY OF THE PERSONAL ADJUSTMENT AND ROLE SKILLS QUESTIONNAIRE AND A SIMILAR COVER LETTER. QUESTIONNAIRE PACKETS SENT TO THE INCENTIVE AND NO-INCENTIVE GROUPS WERE IDENTICAL EXCEPT FOR THE 25 CENTS TAPED TO THE INCENTIVE GROUP'S COVER LETTER AND A STATEMENT ASKING RECIPIENTS TO ACCEPT THE MONEY AS A TOKEN OF APPRECIATION. ALL SUBJECTS RECEIVED A SELF-ADDRESSED, PREPAID ENVELOPE. IF THE QUESTIONNAIRE WAS NOT RETURNED WITHIN 10 MAILING DAYS, SUBJECTS WERE SENT A LETTER URGING THEM TO RETURN IT. AFTER 7 ADDITIONAL MAILING DAYS, UP TO TWO TELEPHONE REMINDERS WERE MADE REQUESTING RESPONSES. THE 1-MONTH RETURN RATES WERE COMPARED USING CHI SQUARE ANALYSIS, WITH RESULTS INDICATING THAT THE INCENTIVE GROUP RETURNED SIGNIFICANTLY MORE QUESTIONNAIRES (89 PERCENT) THAN THE NO-INCENTIVE GROUP (67 PERCENT). ANALYSIS OF THE 3-MONTH QUESTIONNAIRE DATA SHOWED THAT THE INCENTIVE GROUP RETURNED 83 PERCENT OF THE QUESTIONNAIRES AND THE NO-INCENTIVE GROUP RETURNED ONLY 63 PERCENT. THUS, STUDY RESULTS CLEARLY INDICATE THAT A SMALL MONETARY INCENTIVE SIGNIFICANTLY INCREASES THE LIKELIHOOD OF RETURNED QUESTIONNAIRES. TABULAR DATA AND REFERENCES ARE INCLUDED. (PRG)