For operational and analytical purposes, the World Bank classifies member countries and all other economies with populations of more than 30,000 in several categories according to 3 criteria :
Geographic region: Classifications and data reported for geographic regions are for low-income and middle-income economies only. Low-income and middle-income economies are sometimes referred to as developing economies.The use of the term is convenient; it is not intended to imply that all economies in the group are experiencing similar development or that other economies have reached a preferred or final stage of development. Classification by income does not necessarily reflect development status.
East Asia and Pacific;
Europe and Central Asia;
Latin America and the Caribbean;
Middle East and North Africa;
Income group: Economies are divided among income groups according to 2013 gross national income (GNI) per capita, calculated using the World Bank Atlas method. GNI (gross national income : GNI is similar to gross national product (GNP), except that in measuring the GNP one does not deduct the indirect business taxes) per capita. The groups are:
LI: low income, $1,045 or less;
LM: lower middle income, $1,046-4,125;
UM: upper middle income, $4,126-12,745;
HI: high income $12,746 or more.
IDA (International Development Association) countries: those that had a per capita income in 2013 of less than $1,215 and lack the financial ability to borrow from IBRD (International Bank for Reconstruction and Development). IDA loans are deeply concessional — interest-free loans and grants for programs aimed at boosting economic growth and improving living conditions.
IBRD countries: qualify to IBRD noncessional loans.
Blend countries: eligible for IDA loans because of their low per capita incomes but are also eligible for IBRD loans because they are financially creditworthy.