Optimal Pricing with Costly Adjustment: Evidence from Retail-Grocery Prices

In many theoretical models, it is assumed that there are costs associated with adjusting prices. In this paper, the existence, type, and magnitude of such costs are investigated empirically. A discrete-choice dynamic-programming model that nests fixed and variable costs is developed, and econometric estimates of the adjustment-cost function are obtained. The data used to implement the model consist of weekly retail prices and sales of three brands of saltine crackers sold by four chains of grocery stores in a small U.S. town. The study has several distinguishing characteristics. First, the data are highly disaggregate (at the level of brand and store). Second, variables are sampled at weekly intervals. Third, the model nests fixed- and variable-adjustment costs and can therefore determine their relative importance. Finally, the discrete-choice model is both structural and dynamic.