Base independence in the analysis of tax policy effects

The analysis contrasts results of two recently expounded micro-level data approaches to derive robust intertemporal characterizations of redistributional effects of income tax schedules; the fixed-income procedure of Kasten, Sammartino and Toder (1994) and the transplant-and-compare method of Dardanoni and Lambert (2002). Our study is normative in that the Blackorby and Donaldson (1984) index of tax progressivity is employed. This enables contributions from vertical redistribution and horizontal inequity also to be assessed, using for the latter one classical measure and one no reranking measure. When the competing methodologies are applied to Norwegian data for 1992–2004, their respective strengths and weaknesses are revealed. The transplant-and-compare procedure is found to have a number of advantages.