The intelligence quotient, or IQ, is meant to provide a measurable score of intellectual ability. Currently, three major adult IQ tests measure various types of intelligence and cognitive skills through both verbal and nonverbal questioning. Generally, these tests measure reasoning, memory, comprehension and processing speed. Additionally, nonverbal tests are sometimes used for test takers who do not perform well on standardized tests or who have been diagnosed with a psychological or learning disorder.
Stanford-Binet Intelligence Scales
The Stanford-Binet IQ test was first published in 1916 and has been revised five times. This test uses both a point scale and an age scale, which gives test takers both a point total and an age that corresponds to their intelligence. The current format of the test measures knowledge, fluid reasoning, quantitative reasoning, visual-spatial processing and working memory. Each of these types of cognitive ability are measured both verbally and non-verbally.
Wechsler Adult Intelligence Scale
The Wechsler Adult Intelligence Scale, or WAIS, was developed in 1955 and is currently in its fourth version, which was published in 2008. The current version of the test includes 10 subtests and five supplemental tests, which provide the test taker with a full scale IQ and a general ability index. The test taker receives a verbal comprehension index, a perceptual reasoning index, a working memory index and a processing speed index. To obtain the verbal comprehension index, the test includes similarities, vocabulary, information and comprehension sections. The perceptual reasoning index is obtained from block design, matrix reasoning and visual puzzle tests. Working memory is tested through digit span and arithmetic while processing speed is testing through symbol search and coding.
Woodcock-Johnson III Tests of Cognitive Abilities
The Woodcock-Johnson is a cognitive assessment that determines cognitive abilities, processes and academic performance. The series tests seven general abilities: comprehension-knowledge, long-term retrieval, visual-spatial thinking, auditory processing, fluid reasoning, processing speed and short-term memory. Test types include verbal comprehension, spatial relationship, sound blending, visual matching, general information, auditory attention, decision speed, rapid picture naming and number series. Additional test types focus on variations of the seven overarching abilities. The test is used to develop instructional interventions through knowledge of an individual student's cognitive strengths and weaknesses.
Raven's Progressive Matrices
Another test of general intelligence, Raven's Progressive Matrices, assesses IQ through visual problem solving. Using Geometric figures, the test taker completes analogy and similarity questions. Raven's Progressive Matrices will often result in higher IQ scores for test takers with autism and Asperger's syndrome than results in a verbal-based IQ test like Stanford-Binet and WAIS.