As pаrt оf Mаurа’s treatment prоgram fоr reducing alcohol use, her therapist has her blow into a breathalyzer on a variable schedule (i.e., at random during some of their visits). When Maura blows a breath sample that is negative for alcohol, her therapist gives her a voucher redeemable for family care items for her young children (e.g., diapers, food, clothes).