Purchase frequency, sample selection, and price sensitivity: The heavy-user bias

We study the relationship between purchase frequency and volume and choice behavior as summarized by brand preferences and price sensitivity. Our most striking finding is that consumers with high purchase frequency or high purchase volume are much more price sensitive and have more sharply defined preferences for national brands than consumers with low frequency or low volume of purchase. In much of the choice literature, analysis is confined to households that have on average a larger number of purchases than is representative of the ERIM panel. Our findings suggest that some caution should be exercised in interpreting studies that employ purchase-frequency or purchase-number sample inclusion rules. Our findings also support an information theoretic point of view in which households become more price sensitive via costly acquisition of information about the distribution of prices.