Historically, even before IQ tests were devised, there were attempts to classify people into intelligence categories by … See more

There are a variety of individually administered IQ tests in use in the English-speaking world. The most commonly used individual IQ test series is the Wechsler Adult Intelligence Scale (WAIS) for adults and the … See more

Psychometricians generally regard IQ tests as having high statistical reliability. Reliability represents the measurement consistency of a test. A reliable test produces similar scores upon repetition. On aggregate, … See more

Environmental and genetic factors play a role in determining IQ. Their relative importance has been the subject of much research and debate.
The general figure for the heritability of IQ, according t… See more

In general, educational interventions, as those described below, have shown short-term effects on IQ, but long-term follow-up is often missing. For example, in the US, very large intervention programs such as the … See more