Throughout the United States, school systems are supplementing teachers' incomes as a reward for the guidance and supervision of students who participate in extracurricular activities. To provide school officials with current data on supplementation, in the fall of 1988 1,737 comprehensive surveys requesting teachers' and other selected professionals' wages and salary schedules for 1988-89 were mailed to a national sample of public school systems stratified by pupil enrollment. Of the 1,094 responding districts, 578 provided suitable information for analysis. Within this document, the maximum scheduled supplements are reported under the activities categories of: (1) head varsity athletics (senior high); (2) head varsity athletics (junior high); (3) assistant varsity athletics; (4) nonathletics (senior high); and (5) nonathletics (junior high). The study's results are presented and analyzed according to four enrollment groupings, five per-pupil-expenditure levels, and eight geographic regions. The results indicate that more that 68 percent of the districts supplement the salaries of teachers who perform extra duties and that the highest average maximum supplement for head athletic positions is $3,696.00 and the highest average maximum supplement for nonathletic positions is $2,919.00. (KM)