Stanford-Binet Intelligence Scale

The Stanford-Binet Intelligence Scale is an individually administered assessment of intelligence and cognitive abilities. The Stanford-Binet has a wide variety of uses, including school placement, determining the presence of a learning disability or developmental delay, and tracking intellectual development. Although undergoing various revisions, this assessment tool is the oldest and most influential test of its kind.

The test was originally developed in 1905 by Alfred Binet, a French psychologist, along with his colleague Theodore Simon, as a mechanism to identify school-children who were in need of special education in France. The test consisted of 30 tasks of increasing difficulty that assessed such factors as attention, memory, and verbal skills. The test, referred to as the Binet-Simon scale, was revised in 1908 and 1911. In the revised version, tasks were clustered by the age at which most children could successfully complete them. The number of tasks successfully completed measured the child's level of intellectual performance, which Binet referred to as “mental age.” To allow for a broader age range, adult tasks were added in the revision.

In 1916, the first U.S. revision was completed by Lewis Terman at Stanford University. Terman recognized the limitations of using the Binet-Simon scale in the United States because the research was based on a different population. While Terman employed many tests from Binet's scale, he incorporated new tests based on his own methodical research. His research provided a better representation of the population and included a higher and lower age range. The test was commonly referred to as the Stanford-Binet Scale.

The Stanford-Binet Scale was carefully standardized, based on extensive research by Terman and his team of graduate students. The test's organization, administrative procedures, and scoring instructions were made clearer. The most important aspect of Terman's revision was incorporating William Stern's concept of intelligence quotient (IQ). IQ was defined as the ratio of mental age to chronological age multiplied by 100. The concept of IQ replaced Binet's “mental age.”

After over two decades, Terman and his colleague Maud Merrill released another revision in 1937. This revision addressed the limitation of the 1916 single-form version by developing two carefully equated scales: Form L and Form M. Each form consisted of 129 tests that contained more performance-based tasks and less verbal testing. The test covered Ages 2 through adult, and the test integrated the use of toys to keep younger test takers interested.

For their third revision, Terman and Merrill published Form L-M, which consolidated the best items from the two previous forms. The use of the traditional IQ was eliminated and replaced with Deviation IQ, which was based on a standardized score. In 1973, revised norms of the Stanford-Binet were released by Robert Thorndike.

The Stanford-Binet Intelligence Scale, fourth edition, was released in 1986 by Thorndike, Elizabeth Hagen, and Jerome Sattler. This revamped version used a point-scale as opposed to the age-scale from previous forms. The point-scale is an arrangement of tests into subtests with items organized by type and presented by varying difficulty. The subtests, which provided a score for each area, focused on the following: general intelligence, verbal reasoning, abstract/visual reasoning, quantitative reasoning, and short-term memory. The vocabulary section was used to help the administrator determine where to begin testing.

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