Market statistics for the Dirichlet model: Using the Juster scale to replace panel data

The well-known NBD-Dirichlet model of purchase incidence and brand choice is usually estimated from aggregate market statistics such as penetration, average purchase frequency, and market share. In practice, panel data have been the only accurate source of this information. This research developed estimators of these market statistics based on the Juster scale, an 11-point purchase probability scale that can be applied using a survey. A validation study, involving comparisons with panel data for 16 brands in three categories, showed that the Juster-based estimators performed very well. This result allows the data requirements of the NBD-Dirichlet model to now be satisfied using a survey. (C) 2002 Elsevier Science B.V. All rights reserved.