[Poverty in Mexico. I. Methodology and evolution]

This article is the first of two parts of a research report on the evolution and magnitude of poverty in Mexico. Herein are presented the methodologies used in both parts and the evolution of poverty. The Poverty Line methodology (PL), in its Standard Basket of Essential Satisfiers version, is succinctly explained. Two problems on the definition of normative requirements are emphasized: the foundations of such requirements and the access route by which needs are to be met (private consumption or public transfers). Identification of six household welfare sources allows for criticism of PL and Unsatisfied Basic Needs methodologies which the Integrated Poverty Measurement Method (IPMM) brings together. IPMM is used to estimate the magnitude of poverty in 1989. The results are presented in the second part of this report. Results analyzed in the last section of this article show that while poverty in Mexico decreased steadily from 77.5% in 1963 to 48.5% in 1981, it increased since 1982, reaching 66% in 1992.