Utilizing the commodity purchase task to evaluate behavioral economic demand for illicit substances: a review and meta‐analysis

Abstract

Background andAims The commodity purchase task is a simulated demand procedure that is easy and quick to complete (< 5 minutes) as well as adaptable for remote delivery and use with varied study populations. The purpose of this meta‐analysis was to synthesize research using the commodity purchase task with illicit substances to evaluate the magnitude of omnibus effects sizes and moderators of the correlation of demand indices with quantity–frequency (QF) and severity measures. Design Random‐effects meta‐analyses and meta‐regressions involving studies with cross‐sectional correlational designs. Setting and Participants Eleven studies, 10 outcomes and 2146 participants from two countries (USA and UK) published up to 1 October 2018. Measurements Omnibus effect sizes (correlation coefficients) of five demand indices from the commodity purchase task [intensity (unconstrained consumption), elasticity (price sensitivity), Omax (maximum expenditure), Pmax (price at maximum expenditure) and breakpoint (first price of zero consumption)] with QF and severity measures. Meta‐regression models tested moderators of effect sizes (i.e. sample age and sex composition, commodity type and number of prices used in the commodity purchase task). Findings Significant omnibus effect sizes were observed with QF and severity measures for intensity (r = 0.32/0.28, QF/severity, respectively), elasticity (r = −0.14/−0.18), Omax (r = 0.30/0.29) and breakpoint (r = 0.17/0.22) values. Pmax was only significantly associated with severity measures (r = 0.15). The percentage of female participants and number of prices used in the purchase task significantly moderated Pmax and breakpoint effect‐size estimates in that stronger associations were observed in samples with a greater percentage of women and in studies using tasks with more price points. Commodity type (cannabis versus cocaine) did not significantly moderate associations involving any demand index. Conclusions Behavioral economic demand as measured by the commodity purchase task is consistently correlated with measures of illicit substance use quantity–frequency and severity.

Quantifying the Impact of Public Perceptions on Vaccine Acceptance Using Behavioral Economics

“…Using this methodology, evidence robustly supports relations between simulated demand assessments and concurrent and prospective prediction of real-world public health behaviors (8,14,18). However, limitations of the current study include non-probability sampling and assessment of intentions and selfreported histories, rather than actual vaccinations; note, however, prior evidence has shown a correspondence between seasonal influenza vaccination and pandemic influenza vaccination (32).…”

“…Purchase tasks require respondents to report their willingness to obtain a commodity at different prices, level of effort, or some other qualifying trade-off, and can provide a snapshot of consumption intentions under different market conditions. Such hypothetical purchase tasks simulate demand and significantly relate to or predict actual consumption (12,13) or clinical measures associated with substance consumption (14,15). Although such hypothetical tasks will never substitute for real, observed consumption, existing research suggests these are useful proxies when assessment of real-world behavior or other direct observation is impractical (16).…”

“…Existing behavioral economic research using simulated purchase tasks has shown them reflective of real-world behaviors in diverse public health arenas (e.g., sexual activity, substance use) (8,14,18). Behavioral economic procedures are particularly well-suited for forecasting intentions regarding consumption of novel commodities.…”

Concurrent validity of the alcohol purchase task in relation to alcohol involvement: protocol for a systematic review and meta-analysis

“…A recent meta-analysis on the concurrent validity of illicit purchase tasks has shown that sex and number of prices used are significant moderators of the relationship between P max , breakpoint and quantity and severity measures. 15 Also, consistent with the evidence of sex differences in alcohol use and related problems, 16 17 some studies have reported sex differences in demand, 18 19 but with divergent results on both the significance and the directionality of associations between APT indicators, making the results tentative so far. Combining individual APT studies allow meta-analysing potential moderators in a more cost-effective and powerful approach than any single study could do.…”

Commentary on Strickland et al. (2020): Do commodity purchase tasks provide clinically meaningful indices of motivation to consume drugs?

“…Strickland et al . extend this literature with their timely and rigorous meta‐analytical summary of the smaller but growing body of literature examining illicit drug purchase tasks. A relative challenge with drug purchase tasks is the lack of standardization of drug doses and varieties compared to alcohol standard drinks.…”