Grossing-Up and Validation Issues in an Italian Tax-Benefit Microsimulation Model

The aim of this paper is to give a detailed description of TABEITA, the tax-benefit Micro Simulation Model (MSM) developed and maintained at Econpubblica (Center for Research on the Public Sector, Bocconi University) for the analysis of the redistributive impact of the Italian Personal Income Tax. After a brief general introduction on the scope and main features of MSMs, all the main characteristics of TABEITA are discussed. Particular emphasis is posed on issues that are crucial for the reliability of a MSM: the grossing-up procedure and the validation of model outputs. A sample simulation of the 2004 and 2005 PIT reforms are reported in order to show one of the possible applications of the MSM. A concise guide for TABEITA users is provided in the appendix