Habits, Complementarities and Heterogenenity in Alcohol and Tobacco Demand: A Multivariate Dynamic Model

Abstract

In this paper we test the existence of rational habit formation in a multivariate model for alcohol and tobacco consumption. The theoretical framework, based on a dynamic adjustment cost model with forward-looking behaviour, is enhanced to include the intertemporal interactions between the two goods. The analysis of the within-period preferences completes the intertemporal model, allowing to evaluate the static substitutability/complementarity relationships. The empirical strategy consists in a two step estimation procedure. In the first stage, the parameters of the demand system are obtained, while in a second stage Euler equations are estimated by a dynamic fixed-effects panel data model. Estimation results, based on a cohort dataset constructed from a series of crosssections of the ISTAT Italian Household Budget Survey, reveal a significant complementarity relationship between alcohol and tobacco. The Euler system estimation does not reject the hypothesis of intertemporal dependence, providing support for a forward-looking behaviour in alcohol and tobacco consumption. Moreover, we find significant intertemporal interactions for tobacco adjustments, while alcohol consumption seems to follow only its own adjustment dynamics.alcohol and tobacco consumption, cohort data, adjustment cost model, intertemporal interactions, GMM.