Interdependent group contingency management for cocaine-dependent methadone maintenance patients.

Researchers worked with the adults in a methadone clinic. All had cocaine use disorder.

The team set up a group token system. If every member stayed clean and came to group, one random person won a $50 gift card.

They flipped the rule on and off four times to be sure any change came from the rule.

When the rule was on, more patients showed up for group sessions.

Adding a second rule—attend group AND stay clean—pushed attendance a little higher.

Cocaine use stayed flat, but people kept coming back.

Allison (1976) ran a similar token plan in a fourth-grade classroom. Both studies show group contingencies work across ages and settings.

Marcucella et al. (1978) used a three-person rule in a lab. Their ABAB design matches this clinic study, proving the method travels outside schools.

Weinsztok et al. (2022) found bigger prizes protect treatment when staff slip. C et al. echo this: a single $50 prize moved adults, hinting that size still matters.

You can use one anonymous client to carry the whole group. Pick a random name after the session; if that person met the goal, everyone earns the prize. This keeps cost low while peer pressure stays high. Try it next time attendance drops in day-treatment or outpatient groups.