The dynamics of price elasticity of demand in the presence of reference price effects

The authors derive an expression for the price elasticity of demand in the presence of reference price effects that includes a component resulting from the presence of gains and losses in consumer evaluations. The effect of reference price is most noticeable immediately after a price change, before consumers have had time to adjust their reference price. As a result, immediate-term price elasticity is higher than long-term elasticity, which describes the response of demand long after a price change, when reference price effects are negligible. Furthermore, because of the differential effect of gains and losses, immediate-term price elasticity for price increases and price decreases is not equal. The authors provide a quantitative definition for the terms immediate term and long term, using the average interpurchase time and the discrete "memory" parameter. Practical consequences of the distinction between immediate- and long-term elasticities for the estimation and use of elasticity values are discussed.