No test will tell you 100 percent whether you're a brainiac or not, but some can be good indicators.
First introduced by the French psychologist Alfred Binet, IQ --- or "Intelligence Quotient" --- was originally conceptualized for diagnosing mental retardation in children. A ratio of a child's mental age against his chronological age, "ratio IQ" was later deemed inappropriate for measuring intelligence in adults.
From "Ratio IQ" to "Deviation IQ"
Scores on modern tests are no longer quotients or ratio IQs, but rather "deviation" IQs. Given equivalent percentile ranks --- such that a rank of 99 percentile places one in the top 1 percent of his age group, 95 percentile in the top 5 percent, and so on --- deviation IQ measures the deviation of a person's intelligence from the average intelligence of others of the same age. With the term "IQ" being technically inaccurate, the term "intelligence test" is more commonly used.
Standardized and Norm Referenced Tests
Also called "potential-based assessments," intelligence tests predict an individual's intellectual or academic performance with high degrees of confidence. Provisioned for controlling the elements of the testing process, most intelligence tests are standardized. Characterized by stringent test criteria, standardized tests have set procedures governing test administration, question wording and acceptability of answers.
"Norm-referenced" tests recognize the influence of various factors ---such as culture--- on test performance. "Norming" a test involves a prior administration of the test to large numbers of subjects for whom the test is designed. Individual scores in a norm-referenced test are compared against group performance --- thus, norm-referenced tests determine how well one performs compared to people of his age and of the same culture.
Common Intelligence Tests for Children
The first intelligence tests were designed for children, most widely-used of which is the Stanford-Binet Intelligence Scales, which had undergone as many as five editions. Other widely-used intelligence tests for children include the Cognitive Assessment System (CAS), the Kaufman Assessment Battery for Children (KABC) and the Wechsler Intelligence Scale for Children (WISC).
Intelligence Tests for Adults
Called the Wechsler Adult Intelligence Scale (WAIS), this first and most widely-used intelligence test for adults was designed by David Wechsler during the 1930s. A version for children followed soon after. The latest edition of the Stanford-Binet Intelligence Scales (SBIS-V) covers older age ranges as well.
Non-Verbal Intelligence Tests
Some standardized tests tend to discriminate against children with verbal expression difficulties, whether due to physical impairment, language difficulty or lack of confidence. Designed to offset these disadvantages, non-verbal tests involve as little verbal expression as possible or none at all. Some of the most widely used non-verbal intelligence tests are the Comprehensive Test of Nonverbal Intelligence (CTONI), the Universal Nonverbal Intelligence Test (UNIT) and Raven's Progressive Matrices.
