IMPLICATIONS FOR ASYMMETRY, NONPROPORTIONALITY, AND HETEROGENEITY IN BRAND SWITCHING FROM PIECE-WISE EXPONENTIAL MIXTURE HAZARD MODELS

The authors develop a class of mixtures of piece-wise exponential haza rd models for the analysis of brand switching behavior. The models ena ble the effects of marketing variables to change nonproportionally ove r time and can, simultaneously, be used to identify segments among whi ch switching and repeat buying behavior differ. Several forms of asymm etry in brand switching are accommodated. The authors provide an appli cation to the analysis of scanner panel data on ketchup, which illustr ates the implications for asymmetry, nonproportionality, and heterogen eity. The results show that the model predicts purchases and purchase timing in holdout data better than the models proposed by Kamakura and Russell (1989) and Vilcassim and Jain (1991).