Intelligence Quotient (IQ) tests are designed to measure the intellectual capacity of an individual as compared to the general population. A person's mental performance in several areas, including fluid intelligence, memory, processing speed, and quantitative reasoning, may be estimated by using these standardized tests. These tests may be used in adults to measure brain damage after illness or trauma or even as a prescreening for employment. IQ tests are often used to predict future academic success by ascertaining the potential of a child to learn.
For adults, the most commonly used IQ tests are the Wechsler Adult Intelligence Scale™ (WAIS™) and the Stanford-Binet Intelligence Scales™. Both tests are extremely accurate, and subsequent testing reveals only small discrepancies in previously recorded IQ scores. The Stanford-Binet™ is broken into more subsets than the WAIS&trade, however, and may take longer to administer. Conversely, the WAIS™ is more limited in testing working memory.
Intelligence assessments of children are generally used when the child has shown either substantial delays or obvious giftedness. These tests are primarily used to assure that proper services are provided to these children. IQ tests for children may include the latest versions of Wechsler Intelligence Scale for Children&trade (WISC&trade), the Kaufman Assessment Battery for Children&trade (KABC™), or the Wechsler Preschool and Primary Scale of Intelligence&trade (WPPSI™). Of these, the WISC™ and the WPPSI™ are primarily paper-and-pencil tests, while the KABC™ relies primarily on manipulative and verbal responses. The WPPSI™ is one of the few tests designed to measure general intelligence in children under three years of age.
As many IQ tests rely heavily on language and verbal skills, individuals with difficulties in these areas often require special testing. The Test of Nonverbal Intelligence&trade (TONI™) and Universal Nonverbal Intelligence Test&trade (UNIT™) were developed to act as reading- and language-free assessments of intelligence. These tests are particularly useful in hard-of-hearing individuals and non-English speaking subjects. For autistic individuals, the tests often give a more accurate reading of true intelligence than traditional tests. Still, the results may be skewed as the tests are usually given by people unfamiliar with the condition.
Many online IQ tests are available. Generally, these tests are extremely unreliable and bear only a passing resemblance to scientifically developed standardized testing. These tests often give highly inflated scores and should be considered for entertainment purposes only.
Formalized intelligence testing has come under fire as potentially biased. In many cases, the arrangement of certain tests measures learning rather than the potential to learn. In those instances, those from affluent families who have been exposed to richer learning environments frequently score higher than those from economically disadvantaged homes. In addition, most IQ tests are designed for individuals native to the countries in which the tests are administered. As most tests involve written or spoken components, non-native individuals are regularly at a disadvantage.