The Stanford-Binet IQ test provides a way to measure the intelligence of a subject. Though the test began as a measure of general intelligence, the history of the stanford-binet test shows that it has evolved to include other useful measures as well. The current version, published in 2003, tests eight abilities including the original French general intelligence test of 1905.

Intelligence test concept introduced in 1905

The Binet-Simon Intelligence Test, a collaboration of Alfred Binet and Theodore Simon, was first published in 1905 in L’Ane’e Psychologique. Binet was a French psychologist and Simon was his student. Their test, commissioned by the French government, was designed to measure the level of intelligence in children thought to be mentally retarded.

Improvements on their original test continued as additional research was conducted.
New versions of the test became available in 1908, and again in 1911. The updated tests were formulated using both mentally retarded subjects and subjects thought to be of normal intellect, creating a baseline from which to compare. The original test did not include normal examinees.

Stanford University develops improved test for Americans

Stanford University’s Lewis Terman and his colleague, Maud Merrill, worked over the next 20 years to develop additional forms of the original French test for use in the United States. Their parallel forms, named Form L and Form M, provided a better sampling of populations and abilities. The improved test, named Stanford-Binet, was published in 1937 and used a broader representation of upper and lower ability levels.

Merrill, having begun her work on the Stanford-Binet project as Terman’s student and later as a research collaborator and professor on the Stanford University staff, continued to research and revise the test into the 1950’s. Combining the 1937 Forms L and M into one, Form L-M was published in 1960. It was further improved and new items added at every level, with the 1973 version still maintaining the format of those published in 1937.

Fourth and Fifth Editions

The Fourth Edition of the Stanford-Binet Intelligence Scale, published in 1986 by Thorndike, Hagen, & Sattler, added 28 items and changed the format from age-scale to point-scale. Subtests added to the Fourth Edition included verbal and visual reasoning tests, short-term memory tests, quantitative reasoning, and equation building and matrices. Though these test items may have been used in the past, there was no means to provide scores for them. The new version provided a means to assign and record numerical points.

Combining both of the scoring formats from earlier forms and newer research, the Fifth Edition, SB5, was published in 2003 by Roid. This latest version reintroduced the age-scale scoring for portions of the test. In addition, it was designed to keep various items in each test level to help maintain the interest of the examinee.

Development of the test structure

The initial 1916 Stanford-Binet Intelligence Test measured general intelligence using a single age scale and parallel vocabulary testing. The 1937 and 1973 versions also measured general intelligence abilities using similar vocabulary and age scales, with the 1937 version using a parallel age scale.

It wasn’t until 1986 that more items were added to the tests. The items added in addition to general intelligence were verbal reasoning, visual and abstract reasoning, quantitative reasoning, and short-term memory. The structure of the test became one of subtests with point scales and vocabulary routing.

By the year 2003, the Fifth Edition had added even more items. The structure was now hybrid and used both verbal and nonverbal routing and age scales. In addition to the previous versions’ general intelligence and quantitative reasoning tests, knowledge, fluid reasoning, verbal and nonverbal IQ, and visual-spatial processing were added. The working memory test was replaced in favor of the 1986 short-term memory test.

Debate and research continue

Debate over methods and use of age scale began in 1916 between Lewis Terman and Robert Yerkes and continued throughout the history of The Stanford-Binet IQ Test. Revised and improved throughout its history, the test has included hybrid scoring scales for both age and points. Age scales were once used by examiners to determine a child’s mental age, but aren’t as commonly used at this time. The current use of SB5 subtests given and points scored is most popular today.