Collective consumption and welfare Olivier Donni UniversitØ de Cergy-Pontoise Abstract In this paper, we present a collective model of household demand based on Pareto-e¢ciency. In addition, we suppose that (a) each household member is egoistic and consumption is purely private, (b) there is a set of distribution fac- tors and (c) there is one exclusive good. Then we derive the testable restrictions which are implied by this theoretical setting and show how welfare comparisons at the individual level can be performed. Keywords : collective models, household demands, Slutsky matrix, welfare. J.E.L. Code : D11. Forthcoming in The Canadian Journal of Economics. The research was supported in part by the Fonds quØbecois pour la recherche sur la sociØtØ et la culture. A preliminary version of this paper, entitled "A Simple Model of Collective Consumption", has been presented at the European Economic Association Meeting (Venise, 2002) and at the JournØes de MicroØconomie AppliquØe (Montpellier, 2003). We would like to thank Franois Bourguignon and Pierre-AndrØ Chiappori and three anonymous referees for useful comments and suggestions. Of course, we bear the sole responsibility for any remaining errors. 1