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.
Poverty
For a few years starting 1990, the World Bank anchored absolute poverty line as $1 per day. This was revised in 1993, and through 2005, absolute poverty was $1.08 a day for all countries on a purchasing power parity basis, after adjusting for inflation to the 1993 U.S. dollar. In 2005, after extensive studies of cost of living across the world, The World Bank raised the measure for global poverty line to reflect the observed higher cost of living. In 2015, the World Bank defines extreme poverty as living on less than US$1.90 (PPP) per day, and "moderate poverty" as less than $2 or $5 a day (but note that a person or family with access to subsistence resources, e.g., subsistence farmers, may have a low cash income without a correspondingly low standard of living – they are not living "on" their cash income but using it as a top up). It estimated that "in 2001, 1.1 billion people had consumption levels below $1 a day and 2.7 billion lived on less than $2 a day." A 'dollar a day', in nations that do not use the U.S. dollar as currency, does not translate to living a day on the equivalent amount of local currency as determined by the exchange rate. Rather, it is determined by the purchasing power parity rate, which would look at how much local currency is needed to buy the same things that a dollar could buy in the United States. Usually, this would translate to less local currency than the exchange rate in poorer countries as the United States is a relatively more expensive country.