The most reliable and widely used IQ Tests in the world



Intelligence Quotient (IQ) tests are essential tools for measuring human cognitive abilities and are used in various educational and professional contexts.

Quantifying Intelligence Quotient (IQ) through psychometric assessments is a fundamental pillar in cognitive and differential psychology. This document provides a careful analysis of various IQ assessment tools, discussing their psychometric properties, applicability, and the maximum achievable score. The selection of these tests reflects consideration based on their prevalence in academic research and clinical practice, their statistical validity, and their cross-cultural relevance.

This article constitutes a literature review of the most significant and validated intelligence tests used in both academic settings, such as schools and universities, and in scientific studies, including genetic research investigating the hereditary bases of intelligence.


1. Wechsler Adult Intelligence Scale (WAIS-IV):

– Technical Specification: The WAIS-IV is widely considered the gold standard for adult intelligence assessment. With a maximum score of 160, the test evaluates various cognitive domains, including verbal and perceptual reasoning, working memory, and processing speed (Wechsler, 2008).

– Psychometric Robustness: Validity and reliability studies report internal consistency coefficients (Cronbach’s alpha) above 0.90, demonstrating high stability and precision of measurements (Wechsler, D., 2008).

2. Stanford-Binet Intelligence Scales (SB5):

– Technical Specification: The fifth edition of Stanford-Binet is a comprehensive assessment tool that measures five intelligence factors in individuals of all ages, with scores that can vary up to a theoretical limit of 160 points.

– Psychometric Robustness: This test has shown high convergent validity with other intelligence measures, with correlation coefficients often exceeding 0.80 (Roid, G. H., 2003).

3. Raven’s Progressive Matrices:

– Technical Specification: Known for its universal applicability, Raven’s Progressive Matrices assess abstract and logical reasoning, independent of linguistic or educational influences. The test is scored based on percentiles, not a traditional maximum IQ.

– Psychometric Robustness: This tool is valued for its ability to measure fluid intelligence, with studies showing validity coefficients that align with strict criteria for cultural independence (Raven, J., 2000).

4. Wechsler Intelligence Scale for Children (WISC-V):

– Technical Specification: The latest version of the WISC is used to assess children between 6 and 16 years old, with a maximum possible score of 160. This test measures abilities similar to those of the WAIS-IV but adapted for the child population.

– Psychometric Robustness: The WISC-V has shown high levels of reliability (Cronbach’s alpha > 0.90) and validity, with recent studies emphasizing its effectiveness in educational and clinical diagnostics (Watkins & Canivez, 2021).

5. Reynolds Intellectual Assessment Scales (RIAS):

– Technical Specification: The RIAS is a newer tool designed to assess general intelligence as well as immediate memory and processing speed, with scores ranging up to a maximum of 160.

– Psychometric Robustness: The RIAS is recognized for its administrative efficiency and psychometric precision, with validity and reliability comparable to more established scales (Reynolds & Kamphaus, 2003).

The Cattell IQ test is considered a valid instrument within the field of psychometrics. It is distinct for employing an IQ scale that adjusts the score by standard deviation, often using 24 points instead of the 15 points used by many other standard tests, such as those by Wechsler. This results in a wider range of scores.

The Cattell test is especially noted for its focus on measuring fluid intelligence, which is the ability to reason quickly and think abstractly, useful in solving new and unfamiliar problems. It is divided into two forms: Cattell III A, which is verbal, and Cattell III B, which is non-verbal and often preferred in situations where the test taker is not a native speaker of the test language, thus minimizing linguistic bias.

Despite these qualities, the choice of the ideal IQ test should consider the specific purpose of the assessment and the context in which it will be applied, as different tests may be more suitable for different situations or populations. Therefore, the Cattell test is good and useful, particularly when there is an interest in exploring fluid intelligence, but should be chosen consciously, considering the specific needs of the assessment and its limit.

The global intelligence test DWRI, for example, incorporates the previously mentioned tests but also adds assessments that explore creativity, emotional intelligence, social skills, personality traits, behaviors, and a comprehensive cognitive analysis.


The IQ assessment tools analyzed here demonstrate robustness and applicability in various contexts, from clinical diagnosis to educational interventions. IQ tests, such as the WISC, WAIS, and Stanford-Binet, continue to be reliable and fundamental instruments for intelligence assessment, providing essential data for various educational and professional applications. The typical maximum score that these tests can measure is generally around 160, although it may vary slightly depending on specific norms and test editions.

There are numerous other tests that claim to measure intelligence, but they do not reach the same level of utilization or reliability as those discussed in this analysis. Therefore, it is advisable that individuals subjected to these lesser-known instruments also be assessed using one of the validated tests mentioned earlier to confirm the accuracy of their scores.

Even individuals who score above 160 on tests with varied standard deviations or distinct calculation methods should undergo one of the established tests to validate their scores in a comparative and universally accepted manner.


– Watkins, M. W., & Canivez, G. L. (2021). Assessing the Psychometric Utility of IQ Scores: A Tutorial Using the Wechsler Intelligence Scale for Children–Fifth Edition. School Psychology Review.

– Sherman, E., Brooks, B., Fay-McClymont, T., & Macallister, W. (2012). Detecting epilepsy‐related cognitive problems in clinically referred children with epilepsy: Is the WISC‐IV a useful tool?. Epilepsia.

– Hopkins, K., & Bracht, G. H. (1975). Ten-Year Stability of Verbal and Nonverbal IQ Scores. American Educational Research Journal.

– Schuerger, J. M., & Witt, A. (1989). The temporal stability of individually tested intelligence. Journal of Clinical Psychology.

– Nuovo, A. D., Nuovo, S., Buono, S., & Catania, V. (2009). Feedforward artificial neural network to estimate iq of mental retarded people from different psychometric instruments. 2009 International Joint Conference on Neural Networks.

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