Contemporary choice models focus on choice opportunities in which cons
umers purchase a quantity of a single item in a product category, Howe
ver, failing to recognize the possibility of assortments of multiple-i
tem purchases can lead to incorrect conclusions about the impact of pa
st purchase behavior on current choices. The authors propose a model t
hat allows for multiple-item shopping trips and apply it to scanner da
ta for powdered soft drinks. The model provides descriptions about the
influence of (1) consumer's prior behavior across previous shopping t
rips, (2) behavior within the same shopping trip, (3) the in-store she
lf assortment available at the time of purchase, and (4) marketing mix
variables on multiple-item shopping trip choices, The authors' model
provides better choice predictions in a holdout sample at the aggregat
e and assortment composition levels than a traditional, single-purchas
e choice model. Using the model, they present simulation and naturally
occurring experiment results in the powdered soft drinks category, Fi
nally, they discuss the value of their results for understanding the c
onsequences of consumers' choices and their implications for manufactu
rers.