Am. Krieger et al., Effect of level of disaggregation on conjoint cross validations: Some comparative findings, DECISION SC, 29(4), 1998, pp. 1047-1058
Early formulations of conjoint models focused on part-worth estimation at t
he individual level. As the methodology's popularity grew so did industry d
emands for increasingly larger numbers of attributes and levels. In respons
e to these demands, new approaches, based on partial or full data aggregati
on (such as clusterwise/latent class conjoint and choice-based conjoint), h
ave appeared. This paper suggests that pooled-data models will often be suc
cessful in predicting market shares when researchers employ monotonic attri
butes. In these cases more of a good attribute (or less of a bad attribute)
is always more preferred. In the more realistic case, in which some of the
attributes may be nonmonotonic, we find that data aggregation does not pre
dict holdout sample preferences as well as individual part-worth models.