“Sorry, the product you ordered is out of stock”: Effects of substitution policy in online grocery retailing

Postpurchase out-of-stock (PP-OOS) often happens in an online grocery context, where products appear to be available at the time a consumer places an order, but become OOS when the order is to be dispatched. This paper investigates two substitution policies that can mitigate negative responses: substitutions can match (i) on the dominant attribute and (ii) with a product from the consumers’ past purchase portfolio. According to data collected through two computer-simulated purchase experiments, involving more than 3,000 households and five product categories, matching the substitution on the dominant attribute increases acceptance, but this dominant attribute varies across category differentiation level (flavor for horizontal differentiated categories like cereals or crips vs. brand for vertical differentiated categories like margarine or ketchup). Category differentiation also informs acceptance of national brand or private-label flavor substitutes, such that, same-flavor private label is prefered more in horizontal differentiated categories. Matching on the basis of previous purchases has positive effects for both category differentiation levels, and when combining both policies, the previous purchase matching effect grows stronger for same flavor, rather than same brand, matching. These detailed insights establish several key managerial implications for substitution policies in online grocery contexts.