Abstract
OBJECTIVE: To evaluate the association between three behavioural economics 'nudges' and store sales of promoted healthier foods. DESIGN: Multiple interrupted time series. SETTING: Two predominantly rural counties in central North Carolina, USA. PARTICIPANTS: Aggregated store transaction data from two grocery stores (one intervention, one control) and two convenience stores (one intervention, one control) were analysed using ANOVA to examine the association between three 'nudges' and store sales of promoted items. The nudges included: a 'cognitive fatigue' experiment, in which floor arrows guided customers to the produce sections; a 'scarcity' experiment, in which one sign in one area of the produce section portrayed a 'limited amount' message; and a 'product placement' experiment, where granola bars were moved into the candy bar aisle. RESULTS: In convenience stores, there were no significant differences between sales of the promoted items during the intervention period for any of the nudges when implemented individually. However, compared with baseline sales, implementation of all three nudges simultaneously was associated with an increase in sales during the intervention period based on proportional computations (P = 0·001), whereas no significant changes in sales were observed in the control convenience store. Among the grocery stores, there were no significant differences in sales during the intervention period for any of the nudges or the combined intervention compared with baseline sales. CONCLUSIONS: Implementing three nudges concurrently in a convenience store setting may increase sales of promoted items. However, before stores consider implementing these nudges to increase sales of nutritious foods, additional research is warranted.