On the performance of unitary models of household labor supply estimated on “collective” data with taxation

This paper compares collective and unitary models on the basis of simulated collective data with income taxation. We distinguish the cases of individual and joint taxation. Estimating a flexible unitary model, we obtain strikingly different “preference” parameters depending on the type of taxation. We also obtain substantial differences between predicted adjustments to labor supply following a switch between tax regimes. Our results show that even the design of revenue-neutral reforms may be heavily distorted by the use of a unitary model on collective data. Finally, we discuss distortions affecting the welfare analysis of reforms on the basis of unitary estimates when the model generating the data is a collective model. The results suggest that increased efforts should be devoted to the estimation of collective models with taxation.