A construct often used to make the GDP comparable is the GDP per capita, which is derived by simply dividing the GDP by the number of the respective country’s residents. GDP per capita is often used as an indicator for a country’s standard of living and although not perfectly accurate, it provides a decent benchmark.
A concept closely related to the GDP is the Gross National Product (GNP) (also known as Gross National Income (GNI)). In contrast to the GDP, which measures production on a geographic basis, the GNP is calculated based on ownership. Hence, the production of a factory in China that is owned by an American company would be included in the GNP of the USA and in the GDP of China. GNP used to be the official measure of production in the U.S. but has been replaced by the GDP in 1991.
According to this GDP-based country ranking, the U.S. economy is still the largest economy in the world with a Gross Domestic Product of more than 17 trillion U.S. dollars. It is expected though that, given China’s GDP growth rates, the GDP of China will eventually outgrow the U.S. GDP within the next couple of years.
Ranking countries based on per capita GDP yields an entirely different result: In 2014, the three countries with the highest per capita GDP were Luxemburg, Norway and Qatar. The United States of America was ranked 9th behind countries as small as Denmark and Sweden. Meanwhile large, fast growing economies like India, Brazil and China are nowhere to be found in the Top 20.