Types of IQ Tests – WAIS, Raven's, Stanford-Binet & More

Wechsler Adult Intelligence Scale (WAIS)

The Wechsler Adult Intelligence Scale is the most widely administered individual IQ test for adults in the English-speaking world. Originally published by David Wechsler in 1955, it is now in its fourth edition (WAIS-IV), with a fifth edition in use in some clinical settings. The WAIS is designed for adults and older adolescents aged 16 to 90.

The WAIS-IV consists of 10 core subtests and 5 supplemental subtests organized into four index scores:

• Verbal Comprehension – Similarities, Vocabulary, and Information. Measures language-based reasoning, word knowledge, and the ability to express ideas verbally.
• Perceptual Reasoning – Block Design, Matrix Reasoning, and Visual Puzzles. Assesses non-verbal reasoning, spatial processing, and the ability to analyze visual patterns.
• Working Memory – Digit Span and Arithmetic. Tests the ability to hold information in mind and manipulate it mentally.
• Processing Speed – Symbol Search and Coding. Measures how quickly and accurately you can process simple visual information.

The four index scores are combined to produce a Full-Scale IQ (FSIQ) with a mean of 100 and a standard deviation of 15. The WAIS is considered the gold standard for adult intelligence assessment and is frequently used in clinical, educational, and forensic settings. Administration takes approximately 60 to 90 minutes and must be conducted by a trained professional. Learn more about how these subtests translate into a final score in our article on how IQ is calculated.

Wechsler Intelligence Scale for Children (WISC)

The WISC is the counterpart of the WAIS for children aged 6 to 16. Now in its fifth edition (WISC-V), it is the most commonly used IQ test for school-age children worldwide. The structure mirrors the WAIS with age-appropriate content and difficulty levels.

The WISC-V produces five primary index scores: Verbal Comprehension, Visual Spatial, Fluid Reasoning, Working Memory, and Processing Speed. These are combined into a Full-Scale IQ. The test takes about 45 to 65 minutes to administer.

The WISC is widely used to identify learning disabilities, intellectual giftedness, and attention deficits. Schools often rely on WISC results when making placement decisions for special education or gifted programs. Because the test uses age-specific norms, a score of 100 always represents average performance for the child's exact age group.

A related test, the Wechsler Preschool and Primary Scale of Intelligence (WPPSI), extends coverage to children as young as 2 years and 6 months, ensuring that the Wechsler family of tests spans nearly the entire human lifespan.

Stanford-Binet Intelligence Scales

The Stanford-Binet is the oldest continuously used IQ test, with roots stretching back to Alfred Binet's original 1905 intelligence test in France. The current version, the Stanford-Binet 5 (SB5), was published in 2003 and is designed for individuals aged 2 to 85.

The SB5 measures five cognitive factors, each assessed through both verbal and non-verbal subtests:

• Fluid Reasoning – the ability to solve novel problems without relying on previously learned information.
• Knowledge – accumulated information and the ability to apply it.
• Quantitative Reasoning – numerical problem-solving and understanding of mathematical concepts.
• Visual-Spatial Processing – the ability to perceive and manipulate visual patterns and spatial relationships.
• Working Memory – the capacity to hold and process information in short-term memory.

The SB5 uses the same mean-100, SD-15 scale as the Wechsler tests. One of its distinctive features is its wide age range and its ability to measure both very low and very high levels of ability, making it particularly useful for assessing intellectual disability and giftedness. The Stanford-Binet also has a long history of use in research, providing decades of comparative data.

Raven's Progressive Matrices

Raven's Progressive Matrices (RPM) is a non-verbal IQ test developed by British psychologist John C. Raven in 1936. Unlike the Wechsler and Stanford-Binet tests, which include verbal subtests, Raven's relies entirely on visual pattern recognition. The test presents a series of geometric designs arranged in a matrix, with one piece missing. The test-taker must identify the correct missing piece from a set of options.

The test comes in three versions:

• Standard Progressive Matrices (SPM) – 60 items of increasing difficulty, suitable for ages 6 through adult. This is the most commonly used version.
• Coloured Progressive Matrices (CPM) – a simpler version for young children (ages 5 to 11) and individuals with cognitive impairments.
• Advanced Progressive Matrices (APM) – a more challenging version designed to differentiate among higher-ability adults.

Raven's is considered one of the best measures of fluid intelligence – the ability to reason and solve problems independently of learned knowledge. Because it requires no language, it is widely used in cross-cultural research and with individuals who have language barriers or hearing impairments. Many online IQ tests, including our free test, draw inspiration from the matrix-reasoning format pioneered by Raven's.

Cattell Culture Fair Intelligence Test

The Cattell Culture Fair Intelligence Test (CFIT), developed by Raymond Cattell, was explicitly designed to minimize the influence of cultural background, language, and education on IQ scores. It achieves this by using only non-verbal, figural content: series completions, classification tasks, matrix problems, and topology puzzles.

The CFIT comes in three scales: Scale 1 for children aged 4 to 8 and adults with intellectual disabilities, Scale 2 for ages 8 through adult (the most widely used), and Scale 3 for college students and high-ability adults. An important technical detail is that the original Cattell scoring system used a standard deviation of 24 points rather than 15, so Cattell IQ scores appear inflated compared to Wechsler scores. A Cattell IQ of 148 is roughly equivalent to a Wechsler IQ of 130.

The CFIT is valued for its attempt to level the playing field across cultural groups, though research has shown that no test can be completely culture-free. Familiarity with abstract visual patterns, formal schooling, and test-taking experience all provide some advantage regardless of the test format. For more on this issue, see our article on IQ test accuracy and limitations.

Other Notable IQ Tests

Beyond the major tests described above, several other intelligence assessments are worth knowing about:

• Kaufman Assessment Battery for Children (KABC-II) – Developed by Alan and Nadeen Kaufman, this test emphasizes sequential and simultaneous processing. It is designed to reduce cultural bias and is often used as an alternative to the WISC.
• Woodcock-Johnson Tests of Cognitive Abilities (WJ-IV) – A comprehensive battery based on the Cattell-Horn-Carroll (CHC) theory of intelligence, measuring broad and narrow cognitive abilities. It is widely used in educational settings alongside the companion Woodcock-Johnson Tests of Achievement.
• Reynolds Intellectual Assessment Scales (RIAS-2) – A shorter intelligence test that can be administered in approximately 20 to 25 minutes, making it useful for screening and situations where a full battery is not practical.
• Differential Ability Scales (DAS-II) – Designed for children aged 2:6 to 17:11, this test provides a General Conceptual Ability (GCA) score along with cluster scores for verbal, non-verbal reasoning, and spatial ability.

Each of these tests has strengths and limitations, and the choice of which test to use depends on the individual being tested, the referral question, and the clinical context. For a broader discussion of how to choose the right test, see our guide to free IQ tests and our comparison of online versus official IQ tests.

Which IQ Test Is Used in Which Situation?

The selection of an IQ test depends on the purpose of the assessment:

• Clinical diagnosis (intellectual disability, giftedness, ADHD evaluation): WAIS/WISC or Stanford-Binet are most common due to their comprehensive nature and well-established norms.
• Cross-cultural or non-verbal assessment: Raven's Progressive Matrices or the Cattell Culture Fair test are preferred when language and cultural factors need to be minimized.
• Quick screening: The RIAS-2 or the Wechsler Abbreviated Scale of Intelligence (WASI) provide reliable estimates in less time.
• Educational placement: Schools often use the WISC or WJ-IV to inform decisions about special education services or gifted programs.
• Research: Raven's is frequently used in research settings because of its simplicity, wide cross-cultural applicability, and focus on fluid intelligence.
• Personal curiosity: Online IQ tests offer accessible, informal assessments for people who want a quick estimate of their cognitive abilities.