Evaluating an Adjusting Alcohol Purchase Task as a Brief Measure of Behavioural Economic Demand for Alcohol in a Large Sample of Community Adults

Alcohol demand is commonly assessed using hypothetical alcohol purchase tasks (APTs), from which individual demand curves are constructed and yield multiple indices of reinforcing value. Procedurally, APTs can confer participant burden, and existing brief alternatives cannot produce demand curves or derived indices. Thus, we evaluated a novel, adjusting APT that efficiently and idiographically assesses alcohol demand while preserving the benefits of a full task. Adults reporting past-six-month alcohol use (n=897) completed either the adjusting or full APT, the former utilizing a binary-search-style algorithm to administer six prices from the full APT's price set based on level of alcohol demand. The adjusting APT reduced item burden by 49% and produced well-fitting individual demand curves. Average demand intensity and elasticity estimates did not differ significantly by modality, whereas Omax and breakpoint estimates were significantly higher on the adjusting APT, though only by $3 each. All demand indices from both APTs were positively associated with alcohol use and problems, with similar magnitude by modality. Results provide support for the adjusting APT as a brief measure of alcohol demand that retains demand-curve-based indices of reinforcing value.