There is a wide body of literature that establishes the desirable (undesirable) effects of more
equal (unequal) societies in terms of income distribution. These effects include higher degrees of
social cohesion, better public services and societies with more solidarity (Deaton, 2003); lower infant
mortality (Waldmann, 1992), illiteracy rates (Odedokun et al., 2004), and violent crimes (Kelly, 2000).
It also increases happiness (Alesina et al., 2004) and improves general population health (Mellor,
2002).
In the case of Mexico, poverty and inequality levels are among the highest in the OECD,
reaching one and half times that the OECD average country (Baylis et al., 2012). However, studies
about inequality at sub national level in this country have been almost totally neglected until recent
years. Rey and Sastré (2010) used the state per capita income to measure inequality using the Theil
index to test for convergence over a period of 60 years in Mexico. McKenzie (2005) proposed an
inequality measure and proved it using Mexican state level data; however he recognizes that this
data is not statistically representative for all states. In the municipal dimension, Tuirán (2005) in a
report written for the National Population Council uses data from the 2000 Mexican census to
calculate Gini, Theil and 90/10 coefficient for every municipality in the country. Baylis et al. look for
concentration effects of NAFTA using a panel of municipalities (2012).