Poverty
The poverty line threshold of $1.90 per day, as set by the World Bank, is controversial. Each nation has its own threshold for absolute poverty line; in the United States, for example, the absolute poverty line was US$15.15 per day in 2010 (US$22,000 per year for a family of four), while in India it was US$1.0 per day and in China the absolute poverty line was US$0.55 per day, each on PPP basis in 2010. These different poverty lines make data comparison between each nation's official reports qualitatively difficult. Some scholars argue that the World Bank method sets the bar too high, others argue it is low. Still others suggest that poverty line misleads as it measures everyone below the poverty line the same, when in reality someone living on $1.20 per day is in a different state of poverty than someone living on $0.20 per day. In other words, the depth and intensity of poverty varies across the world and in any regional populations, and $1.25 per day poverty line and head counts are inadequate measures.
Mexico
Since late 90s, the majority of the population has been considered to be part of the growing middle class by international economic organizations but according to Mexico's National Council for the Evaluation of Social Development Policy (CONEVAL) from 2006 to 2010 the portion of the population who lives in poverty rose from 18%-19% to 46% (52 million people). However, rather than Mexico's economy crashing, international economists attribute the huge increase in the percentage of population living below the country's poverty line to the CONEVAL using new standards to define it, as now besides people who lives below the economic welfare line, people who lacks at least one "social need" such as complete education, access to healthcare, access to regular food, housing services and goods, social security etc. were considered to be living in poverty (several countries do collect information regarding the persistence of said vulnerabilities on their population, but Mexico is the only one that classifies people lacking one or more of those needs as living below its national poverty line). Said economists do point out that the percentage of people living in poverty according to Mexico's national poverty line is around 40 times higher than the one reported by the World Bank's international poverty line (with said difference being the biggest in the world) and ponder if it wouldn't be better for countries in the situation of Mexico to adopt internationalized standards to measure poverty so the numbers obtained could be used to make accurate international comparisons. According to the OECD's own poverty line (defined as the percentage of a country's population who earns half or less of the national median income) 21.5% of Mexico's population lives in situation of poverty.