There is growing evidence indicating that there can be significant differences between choices made by single individuals and those made by the same individuals when choosing collectively. This study investigates the dissimilarities between individual and joint decision-making in the context of residential location choice. It is widely recognized that household location choices involve several members of a household with heterogeneous preferences and influence power. Nonetheless, little is known about group decision-making processes in practice. In particular, there is only scant evidence on how preferences differ among family members and to what extent individual preferences can be aggregated to achieve an approximation of joint choices. The paper addresses the issue of heterogeneity in single members’ preferences, compares ex ante single preferences and ex post joint choice outcomes, and then quantifies the implicit bias generated by relying on the representative member approach. A set of hypotheses is tested via a two-stage conjoint choice experiment administered to a sample of 78 Italian families. The main novelty of the paper relates to the extension of the dyadic interaction approach to consider the role of adolescents in household decision-making.