A Descriptive Study of Household Shopping Behavior

An important question that has been raised in supermarket retailing is whether weekly promotions induce households to increase their in-store expenditures or merely reallocate a predetermined spending amount in that week. That is, are households ’ grocery shopping expenditures preset before entering the store or are flexible and determined while in the store as a function of the specific store offerings encountered during the store visit? This is an important question for the retailer in light of the vast array of temporary promotions offered to consumers. Indeed, should expenditures be fixed before entering the store (for instance, as a function of the household’s inventory and/or income), it is possible that retailers might decrease their profitability when running promotions by displacing expenditures from high margin items to lower margin products. We claim that to answer this question meaningfully one must consider the totality of the household’s within-store purchases (i.e., the market basket) and not just purchases of the promoted products. Using a rich database that contains the entire basket of goods bought over time by households from a given supermarket chain, we attempt to describe the drivers of bot