Intelligence quotient
Definition and History
The Intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term Intelligenzquotient, his term for a scoring method for intelligence tests at University of Breslau he advocated in a 1912 book.
Historically, IQ is a score obtained by dividing a person's mental age score, obtained by administering an intelligence test, by the person's chronological age, both expressed in terms of years and months. The resulting fraction (quotient) is multiplied by 100 to obtain the IQ score. When current IQ tests were developed, the median raw score of the norming sample is defined as IQ 100 and scores each standard deviation (SD) up or down are defined as 15 IQ points greater or less. By this definition, approximately two-thirds of scores lie between IQ 85 and IQ 115.
Measurement
IQ scores are used for educational placement, assessment of intellectual disability, and evaluating job applicants. Even when students improve their scores on standardized tests, they do not always improve their cognitive abilities, such as memory, attention, and speed. In research contexts, they have been studied as predictors of job performance, and income.
Psychometricians generally regard IQ tests as having high statistical reliability. A high reliability implies that – although test-takers may have varying scores when taking the same test on differing occasions, and although they may have varying scores when taking different IQ tests at the same age – the scores generally agree with one another and across time. IQ scores also correlate with job performance, socioeconomic advancement, and "social pathologies". Recent work has demonstrated links between IQ and health, longevity, and functional literacy.
Theories and Interpretation
Many IQ tests are used today. Whether they are analyzing abstract reasoning, or simple problem-solving abilities, all are supposed to give a quantitative analysis of the test-taker's intelligence. Different types of IQ tests include the Stanford-Binet, Wechsler Adult, and the Kaufman Assessment Battery.
However, the interpretation of these scores has been the subject of ongoing debate. Research has been conducted on whether or not the concept of intelligence is a single factor or a collection of different abilities. This debate is often referred to as "the nature of intelligence" and it is a complex and multifaceted issue.
Criticisms and Controversies
IQ tests have been criticized for being biased towards middle and upper-class individuals, with some arguing that these tests merely measure the skills and knowledge that are valued in those socioeconomic groups. Critics also argue that IQ tests are not accurate measures of intelligence because they do not take into account creativity, personality, character, or wisdom.
Moreover, the use of IQ tests in a variety of social contexts and for numerous purposes has led to an intensification of such criticisms. For instance, in the realm of education, IQ tests have been used to justify controversial policies such as tracking and ability grouping.
