There are different ways to measure poverty. The World Bank says that "extreme poverty" is when someone has less than US$1 a day to live on (that dollar is an ideal one). It has been changed to rule out certain effects such as inflation, meaning that prices of things rise higher than what a person is paid, and other price level differences. "Moderate poverty" is when people have to live on less than $2 a day. In the year 2001, 1.1 billion people were seen as "extremely poor", and 2.7 billion were seen as "moderately poor". 