Although brands have increased their promotional spending substantiall
y in many categories over the past decade, panel-based research into c
onsumer stockpiling behavior typically has assumed that consumers' dec
isions regarding whether and how much to purchase have remained invari
ant to this increase. The authors develop a varying parameter model of
purchase incidence and purchase quantity to ascertain whether this in
crease in promotions has affected households' stockpiling decisions in
the long term. The authors estimate the model on the basis of more th
an eight years of panel data for a frequently purchased, nonfood, cons
umer packaged-goods product. The results suggest that consumers' stock
piling behavior has changed over the years. The increased long-term ex
posure of households to promotions has reduced their likelihood of mak
ing category purchases on subsequent shopping trips. However, when hou
seholds do decide to buy, they tend to buy more of a good. Such behavi
or is indicative of an increasing tendency to ''lie in wait'' for espe
cially good promotions. This change appears to have some deleterious r
amifications for category profitability.