The sensitivity (i.e., elasticity and built-in flexibility) of the U. S. individual income tax to changes in national income is of great interest to researchers and policymakers. However, the direct measurement of this sensitivity—that is, the measurement obtained from time-series observations of the relevant variables—has always been difficult, and even at times impossible, because changes in the legal structure of the tax have been too frequent to provide enough observations that relate to the same legal structure to allow statistically significant coefficients to be determined. This was particularly true in the United States before 1954, when the rates were changed frequently; it has also been true since 1963, when important changes occurred in rates, personal exemptions, deductions, and other features. In contrast, during the period between 1954 and 1963, hardly any significant statutory changes occurred in the tax.
This paper discusses key findings of the Fourth Review Under the Poverty Reduction and Growth Facility (PRGF) for Madagascar. Program performance has been generally good. The authorities have continued to implement sound fiscal and monetary policies that have resulted in good macroeconomic outcomes. They met all of the quantitative performance criteria (PCs) for end-January 2008, but missed two structural PCs. The international reserves cover is expected to deteriorate markedly, prompting the authorities to ask for an augmentation of 15 percent of quota, a request that IMF staff supports.