IQtest

IQ test is a standardized assessment designed to measure a range of cognitive abilities and provide an estimate of general intellectual functioning. A typical result is an intelligence quotient, or IQ, usually presented as a single score with a mean of 100 and a standard deviation around 15 or 16, depending on the test.

The concept emerged in the early 20th century with efforts to identify children needing educational support. The Stanford-Binet Intelligence Scales, developed from Binet's work and later adapted by Lewis Terman, and the scales developed by David Wechsler (Wechsler Adult Intelligence Scale and Wechsler Intelligence Scale for Children) became influential. Nonverbal measures such as Raven’s Progressive Matrices also contributed to assessing abstract problem solving independent of language.

Most modern IQ tests administer multiple subtests that contribute to a full-scale score. Common domains include verbal comprehension, working memory, perceptual reasoning or fluid reasoning, and processing speed. Tests are standardized with age-based norms and require standardized administration by trained personnel. The resulting IQ score is intended as an estimate of general cognitive ability (g), not a complete description of an individual’s talents or potential.

IQ testing is widely used in educational, clinical, and research settings. Online or consumer IQ tests exist, but their validity and reliability vary and they should not be treated as equivalent to professionally administered assessments. Limitations include cultural and language biases, socioeconomic influences, and debates about the scope of intelligence; many psychologists emphasize that intelligence is multifaceted and cannot be fully captured by a single score.