Phase I was a four-week baseline period. Phase II and Phase III were four- and five-week periods, respectively, in which residents were awarded tickets for a weekly ten dollar lottery each day they were at or below a changing criterion of daily fines. In Phase IV, residents received coupons, exchangeable for money, for days with zero fines. Phase V was a return to baseline. Phase VI was a one-week return to baseline. No significant differences in average fines per day, number of residents meeting criteria, or mean number of zero-fine day per week were found across phases. Results are discussed in terms of amount and immediacy of reinforcement, other opportunities to gain money, possible rebelliousness of the residents against the increased aversiveness of fines, and implications for further research. 14 references. (Publisher abstract)