An Introduction to the Taxsim Model

The TAXSIM model is now 17 years old. The original tax calculator was written by Amy Taylor to estimate the effects of tax deductibility on charitable giving [Feldstein and Taylor, 1976]. The model was given its present form several years later by another Harvard student, Daniel Frisch, for a study of the incidence of a proposed integration of the corporate and personal income tax systems [Feldstein and Frisch, 1977]. Subsequent studies by Martin Feldstein, his students, and others proved the data so rich and the model so useful that TAXSIM has been updated every year since and used in scores of NBER projects. This note provides a short history and description of TAXSIM, with special emphasis on the state tax calculator used by six of the papers in this issue of the JPAM.