HIERARCHICAL VERSUS OTHER MARKET SHARE MODELS FOR MARKETS WITH MANY ITEMS

Understanding the competition between products constitutes an importan t problem area in marketing. The existence of many items in a product category requires that researchers consider placing restrictions on th e nature of competition in consumer response models. However, little i s known about the relative appropriateness of alternative model specif ications that differ in constraints. We propose hierarchical models, a nd we compare different possible hierarchies against each other and ag ainst recently developed nonhierarchical specifications. We discuss ho w the alternative specifications accommodate asymmetry in competition, We also show analytical linkages between the different models, and we provide a preliminary empirical comparison of these models based on a ggregate (market-level) scanner data. (C) 1997 Elsevier Science B.V.