Minimum-Bill Thresholds in Promotional Milk Coupon Subscriptions: A Review of Consumer Redemption, Basket Value, and Association Rule Mining

A minimum-bill coupon requires a shopper to reach a specified transaction value before receiving the offer. This paper examines a milk coupon subscription in which the qualifying minimum bill is raised from Rs 99 to Rs 149, an increase of about 50.5%. Through a focused narrative review of studies on coupon redemption, sales promotions, conditional (minimum-spend) promotions and association rule mining in retail, it argues that the higher threshold may encourage some customers to add products to qualify while discouraging redemption among those whose usual baskets fall below the new threshold, so that the net effect on sales and profitability cannot be inferred from the threshold alone. The paper proposes a conceptual framework, five research questions and four hypotheses, and a methodology for future empirical work combining pre-post or comparison-group analysis of redemption and transaction value with Apriori-based market basket analysis, together with a set of evaluation metrics.