Gross Domestic Product (GDP) is the primary indicator to gauge the health a country's economy. It represents the total market value of all final goods and services produced in a country in a given year, equal to total consumer, investment and government spending, plus the value of exports, minus the value of imports.
At its most basic, the calculation can be done in one of two ways: either by adding up what everyone earned in a year (income approach), or by adding up what everyone spent (expenditure method). Logically, both measures should arrive at roughly the same total.
GDP is usually expressed as a comparison to the previous quarter or year. For instance, if the year-to-year GDP is up 3%, this is thought to mean that the economy has grown by 3% over the last year.