In this article, prosperity is defined as the gross domestic product (GDP) per capita, adjusted for price level differences. Differences in price levels have a mitigating effect on differences in the prosperity level. Countries with the lowest GDP per capita also have the lowest prices and consumers can buy more goods and services for the same amount of money. Purchasing power parities are used to determine the relative value of currencies and how much of two different currencies is needed to buy the same basket of goods and services.
The indices reflect the relative prosperity in a country relative to the EU average. Countries with indices above 100 percent have a higher relative level of prosperity per capita than the average across the EU; indices below 100 percent have a lower relative level of prosperity per capita than the EU average.