Measuring the dynamic effects of promotions on brand choice

Promotions are being used with increasing frequency by manufacturers facing highly competitive markets, which is causing concern among some marketers who feel that frequent promotions can hurt a brand. Nevertheless, there is little empirical evidence to either support or dispel such fears. To fill this gap in the literature, the authors propose a brand choice model that provides an estimate of the dynamic effects of promotions on loyalty to the brand and customers' sensitivity to the price of the brand, and measures whether promotional purchases reinforce or reduce subsequent response to similar promotions. They estimate a random effects heteroskedastic covariance probit time-varying parameter model on household scanner panel data from the liquid detergent category. Their results indicate that increased purchases using coupons erode brand loyalty and increase price sensitivity. In addition, the authors find that the effect of features and displays on brand choice is reinforced by prior feature and display purchases, respectivly, as well as by feature and display purchases associated with price cuts. Future research directions are also discussed.