Promotions and Patterns of Grocery Shopping Time

The histograms of interpurchase times for frequently purchased packagedgoods have consistently shown pronounced seven-day cycles. Evidence supports that theweekly spike phenomenon is the result of consumers’ regular shopping trip schedules. Weexplore the implications of this peculiar regularity on the issue of consumer purchase timingacceleration. Data for ® ve product categories are examined. Promotions are found to havelittle eş ect in accelerating purchase timing. In contrast, conventional interpurchase timemodels are shown to overstate the eş ect of promotions.