Reducing the illegal sales of cigarettes to minors: analysis of alternative enforcement schedules.

City teams visited stores every 2, 4, or 6 months. They checked if clerks sold cigarettes to kids under 18.

Stores that broke the law got a ticket and a fine. The study watched what happened next.

Before checks, 86 out of every 100 stores sold to kids. After checks every 2–6 months, only 19 to 42 stores out of 100 did.

Stores with no checks stayed near 84 out of 100. Scheduled enforcement cut illegal sales by more than half.

Barber et al. (1977) used monthly parties to boost school attendance. Einfeld et al. (1996) used months-apart fines to cut cigarette sales. Both show that timing matters: monthly rewards help kids, while spaced-out penalties stop merchants.

Deshais et al. (2019) gave first-graders daily group prizes for worksheet compliance. Einfeld et al. (1996) gave merchants a fine every few months. Daily prizes and rare fines both raise rule-following, but the right pace depends on the setting.

Whiting et al. (2025) lifted college Zoom attendance with a quick weekly poll. Einfeld et al. (1996) needed only a short store visit every few months. Both prove that low-effort, well-timed checks can change behavior without big budgets.

You can copy the city model anywhere rules are broken. Pick a schedule—monthly for classrooms, quarterly for vendors—and pair it with a clear penalty or reward. One quick check can keep compliance high for weeks, saving you time and keeping clients safe.