HDI: Human Development Index- The HDI is a summary composite measure of a country's average achievements in three basic aspects of human development: health, knowledge and standard of living.
GNI: Gross National Income- is defined as gross domestic product, plus net receipts from abroad of compensation of employees, property income and net taxes less subsidies on production.
GDP: Gross Domestic Product- The GDP is the total of all value added created in an economy.
GID: Group Identifier/Group Identification A group identifier, often abbreviated to GID, is a numeric value used to represent a specific group.
PPP: Purchasing Power Parity- an economic theory that compares different countries' currencies through a "basket of goods" approach.
