Comparison of Purchases Between Members of a Supermarket “Wellness Club” Versus Non-Members

Abstract

Abstract Objectives The objectives of this study were to analyze purchase data of two groups of primary shoppers at a local supermarket, one group who were members of a loyalty program focusing on health and nutrition education (e.g., Wellness Club) and another group of non-members to determine if group membership predicted different purchase patterns. Methods A week of aggregated purchases from shoppers identified by loyalty card number were donated from a local supermarket. Shoppers were sorted based on membership within the Wellness Club. Twenty-seven shoppers were randomly selected from each group for a total of 54 shoppers in the sample. Sales of purchased items in dollars and cents were mapped using sub-commodity and UPC descriptions to the 29 categories of the USDA Food Plan. A ratio of spending in each category to total spending of the shopper was calculated. Bivariate linear regression was used to determine if group membership predicted a different ratio of spending in each category. T-tests were conducted to determine if the mean sales within each category and overall were statistically different between groups. Results Results of the bivariate regression indicated that group membership predicted a statistically significantly higher ratio of spending in the dark green vegetables category (B = 0.018, 95% CI [0.006,0.300], r = .376, t(54) = 2.979, P = 0.004, two-tailed). Levene's test indicated unequal variances between groups for all categories except for the whole grain cereal and popcorn and whole grain snacks categories; therefore, Welch's t-test was run for these categories. Mean purchases were statistically significant between groups for each category and the total amount purchased (t(30.056) = 5.689, P < .001, two-tailed), with non-Wellness Club members spending more overall (M = 259.356; SD = 177.813) than Wellness Club members (M = 62.845; SD = 42.370). Conclusions This study found that membership in the Wellness Club predicted a higher ratio of spending on dark green vegetables and that sales were statistically significantly different between groups. Analyzing purchase data may be a useful tool to monitor purchase patterns among shoppers in future supermarket interventions designed to promote healthy food choice. Funding Sources There were no funding sources for this research.