An intelligence quotient, or IQ, test measures the ability to learn. The Army General Classification Test, or GCT, was primarily designed to assess recruits for military jobs. Both tests use a numerical score as their final outcome and are convertible to percentile rankings for a comparison.
The IQ test was first formally developed by Alfred Binet and Theodore Simon in 1904 and was used to identify children who might encounter difficulty in school. It was modified for the American public in 1916 by Stanford psychologist Lewis Terman and became the Stanford-Binet Intelligence Test. Its use coincided with the U.S. Army's development of aptitude tests to screen recruits for military service during the First World War. The Army Alpha and Army Beta tests measured verbal and numerical abilities as well as general knowledge and ability to follow instruction.
The GCT replaced the Army Alpha and Army Beta tests and was used during World War II by both the Army and Navy. It was replaced in 1950 with the Armed Forces Qualification Test that was used by all military branches. In addition to measuring ability to assimilate training, the test also provided information on a recruit's usefulness. The Armed Services Vocational Aptitude Battery was developed to screen and assign recruits and has been used by all branches of the armed services since 1976.