High Quality Content by WIKIPEDIA articles! The Wechsler Adult Intelligence Scale (WAIS) intelligence quotient (IQ) tests are the primary clinical instruments used to measure adult and adolescent intelligence. THe original WAIS (Form I) was published in February 1955 by David Wechsler, as a revision of the Wechsler-Bellevue Intelligence Scale. THe fourth edition of the test (WAIS-IV) was released in 2008 by Pearson. THe Wechsler-Bellevue tests were innovative in the 1930s because they gathered tasks created for nonclinical purposes for administration as a "clinical test battery". BEcause the Wechsler tests included non-verbal items (known as performance scales) as well as verbal items for all test-takers, and because the 1960 form of Lewis Terman's Stanford-Binet Intelligence Scales were less cautiously developed than previous versions, Form I of the WAIS surpassed the Stanford-Binet tests in popularity by the 1960s.