divergent economies, which can result in only rough comparisons. The World Bank has deﬁned the
international poverty line as U.S. $1 and $2 per day in 1993 Purchasing Power Parity (PPP), which adjusts
for diﬀerences in the prices of goods and services between countries. The $1 per day level is generally
used for the least developed countries, primarily African; the $2‐per‐day level is used for middle income
economies such as those of East Asia and La n America.