IQ stands for intelligence quotient, which is a type of test score obtained from certain intelligence tests. IQ is often used simply as a synonym for general intelligence. This entry describes the meaning and use of the intelligence quotient within the history of intelligence test development.

In France at the beginning of the 20th century, Alfred Binet and Theodore Simon were asked by the French government to identify French children with [Page 495]mental retardation so that they could be given an appropriate education. Binet and Simon developed the first modern intelligence test, the 1905 Binet-Simon intelligence scale. This 30-item test was organized so that successive items were more difficult than previous items. By standardizing the scale on groups of children at each age, Binet and Simon ...