The Stanford-Binet is the American revision of the intelligence test originally developed by Alfred Binet and Théodore Simon in France. Lewis Terman of Stanford University adapted and expanded it, introducing the intelligence-quotient concept to a wide audience.

The early versions used the ratio of mental age to chronological age. Later editions adopted deviation IQ scores based on comparison with age peers, bringing the scale into line with modern psychometric practice. The test samples a range of cognitive abilities—verbal reasoning, quantitative reasoning, abstract visual reasoning, and short-term memory—and yields both a composite score and subscale scores.

The Stanford-Binet has been revised repeatedly to update norms, improve fairness, and extend the age range. It remains one of the most carefully constructed and thoroughly researched individual intelligence tests, used in clinical, educational, and research settings. Its history illustrates the evolution of intelligence testing from a practical tool for identifying children who needed help to a sophisticated psychometric instrument.

The scale that carried Binet’s method into American psychology still bears the names of Stanford and Binet.