The Importance of Selling Formats: When Integrating Purchase and Quantity Decisions Increases Sales

Customers must often decide on the quantity to purchase in addition to whether to purchase. The current research introduces and compares the quantity-sequential selling format, in which shoppers resolve the purchase and quantity decisions separately, with the quantity-integrated selling format, where shoppers simultaneously consider whether and how many to buy. Although retailers often use the sequential format, we demonstrate that the integrated format can increase purchase rates. A field experiment conducted with a large technology firm found that quantity integration yielded considerably higher sales, amounting to an increase of more than $1 million in annual revenue. To demonstrate robustness and explore various contributing mechanisms, a series of laboratory experiments test and control for different elements of the selling formats. The results suggest that quantity integration can change the psychology of making a purchase: the integrated format anchors customers later in the decision-making funnel than the sequential format and additional implementation elements (e.g., the specific call-to-action used) may contribute to an increased effect. More broadly, this work sheds light on mechanisms underlying the influence of selling formats and the importance of how everyday choices are structured.