IQ scales - Overview
You can find below a good overview of IQ Test scales. Mainly, 3 types of scales exist: The Wechsler scale, the Stanford-Binet scale and the Cattell scale.
The Wechsler Intelligence Scale (WAIS & WISC)
A wechsler intelligence test is a test that uses the wechsler intelligence scales, created by David Wechsler, an american psychologist, which are a a series of standardized tests used to evaluate cognitive & intellectual abilities.
We can distinguish two different wechsler intelligence scales:
The Wechsler Adult Intelligence Scale (WAIS)
We can use it to measure Adult and adolescent intelligence. The WAIS is was the first created. After, we have created the WAIS-R (WAIS revision). The WAIS-R was divided in two sections: verbal tests and subtests. Then, we were able to obtain a full IQ scale. The WAIS-III is another revision (1997). The main change is the adding of four indices: the verbal comprehension, the working memory, the perceptual organization, the processing speed. Today, the WAIS-IV is used (2008 released) and has 10 subtests, five subtests were added. We removed the verbal and performance scales and replaced them by index scores. We also added a General Ability Index, really good to measure cognitive abilities that are less vulnerable to impairment.
The Wechsler Intelligence Scale for Children (WISC) is used to test chlidren who have from 6 to 16 years old.
The WISC is the first published intelligence test
The WISC-R comes in 1974. 17 years later, the WISC-III was created. In 2010, we use the WISC-IV (released in 2003).
The Stanford-Binet Scale
Stanford-binet scale - Definition
Stanford-Binet intelligence scales have been created by Alfred Binet, a french psychologist. At this time, French government asked him to develop a method to identify intellectually deficient children. Today, there are a lot of Stanford-Binet intelligence scales (fourth Edition, Fifth Edition, etc.). The goal of the Stanford-Binet intelligence scale is to assess (standardized test) the intelligence and cognitive abilities. This concerns the children and the adults from two years old to 23 years (85+ for fifth edition)
Stanford-binet scale - Why do we use it ?
We use the Stanford-Binet intelligence scale to detect children learning disabilities, school maladjustment or retarded intellectual development.
Stanford-binet scale - Description
The first intelligence scale was created in 1905 by Alfred Binet and Theodore Simon. This test has been released a lot of times: The two last editions are: SB4 and SB5 (see below). Four areas of intelligence are tested: The verbal reasoning, the quantitative reasonning, the abstract/visual reasoning and the short term memory.(Knownledge has been added with the SB5 test) 15 subtests covered the areas explained before. They concern these sub-areas: Vocabulary, comprehension, verbal nonsense, pattern analysis, matrices, paper folding and cutting, copying, quantitative, number series, equation building, memory for sentences, memory for digits, memory for objects, and bead memory. To find the score, results are adaptated with the age of the person. The test takes 45 to 90 minutes.
Stanford-binet scale - Brief History
1905:The test was first annonced by Alfred Binet and Theodore Simon. The test has the goal to measure different degrees of mental retardation. Revisions followed in 1908 and 1911.
1916: Lewis Terman adapted and translated the previous test. Other translations and revisions occured in the next years. We call it the "Stanford-Binet" (Terman was at Stanford University)
1937: Terman continued to improve the test. Two forms (L(for Lewis) & M(for Maud)) of the Stanford-Binet were created by Terman. He works with the help of Maud Merrill.
~1950: The two form created in 1937 were combined to create the L-M Form, published in 1960.
1986: The Fourth Edition of the Stanford-Binet Intelligence scale (SB4) is created. Point scale structure is introduced. Items from the prior editions were included.
New sub-tests are created: Matrices, Equation Building. Old factors now offered scores for this testing areas: Verbal reasoning, quantitative reasoning, short-Term memory, Abstract-visual reasoning.
Multi-stage testing is formalized.
2003: The Fifth Edition of the Stanford-Binet Intelligence scale (SB4) is created. Today, we use this scale. This edition takes the advantages of recent research about cognitive measurement. A non-verbal routing test is added. The age-scale is introduced again.
Stanford-binet scale - Stanford-binet 4 (SB4)
Creation date: 1986. The "small" revolution resides in the creation of a point scale structure. To build this test, we use a three-level hierarchical model. These three parts are: The appearance of a general intelligence factor.
Secondly, memory factors are used (crystallized, short therm and fluid memory). Third level: Verbal reasoning, abstract visual reasoning, quantitative reasoning. The sub-tests :
about Matrices and Equation Building are created. We formalize multi-stage testing practice.
Stanford-binet scale - Stanford-binet 5 (SB5)
The Fifth Edition (see history and SB4 for more information) of Stanford-binet scale was published in 2003. This is the last revision. This edition takes the advantages of recent research about cognitive abilities measurement.
On all items we conducted Bias reviews for issues related to ethnicity, culture, religion and socio-economics. 5 factors are tested: Knowledge, Fluid reasoning, Quantitative reasoning,
Working Memory and the visual-spatial abilities. Also, it is interesting to note that these factors are tested two times: First is verbal, second is nonverbal. This results in a more accurate assessment regarding normal intelligence, high-level of giftedness.
The Cattell Intelligence Scale
Cattell scale - Who created it ?
Raymond Bernard Cattell. This person was a British and American psychologist.
Cattell scale - For children
A Cattell scale has been created specifically designed for children. We call it: "The Cattell Infant Intelligence Scale". The goal of this scale is to assess mental ability, mental development for children who have between 2 and 30 months. This test is standardized. Genetic is underlying the view of intelligence.
Cattell scale - Cattell Culture Fair III
He created it to assess intelligence without environmental and genetic factors. He thinks that it consists of fluid intelligence and crystallized intelligence.
