As of April 2015, the country with the highest average IQ is South Korea, which has an average IQ of 106, according to the report "IQ and the Wealth of Nations." While technically not a country, Hong Kong's average IQ, when measured separately from China, is 107, making it higher than South Korea. Other countries that have high average IQs are Japan, Taiwan, Singapore and Austria.
IQ stands for "intelligence quotient," which is a common intelligence test score used in psychology. The abbreviation was first used by William Stern in 1912. The score is calculated by dividing mental age, which is calculated from one of several standardized tests, by chronological age. The result is then multiplied by 100 to obtain an IQ score. A score of 100 is defined as a performance at the average level for that age.
Fourteen countries have average IQs of 100 or greater. The average IQ of the United States is 98, which ranks it 19th among all countries and territories measured. Five countries are ranked alongside the U.S.: Australia, France, Denmark, Norway and Mongolia. The country with the lowest recorded average IQ is Equatorial Guinea, which has an average IQ of 59. Other countries with low average IQ scores include Ethiopia, Sierra Leone and the Democratic Republic of Congo.