Intelligence Quotient scores measure an individual's cognitive abilities. Although there are different kinds of IQ tests that vary according to the age of the person taking the test, most IQ tests measure verbal comprehension, perpetual reasoning, working memory and processing speed. Therefore, an IQ test only measures certain aspects of intelligence.
IQ test results typically follow a statistical pattern known as the bell curve. This pattern means that the majority of test takers receive scores that are in the mid-range, and only a small percentage of test takers receive very low or very high scores. An IQ test is generally scored from one to 200. A score below 70 is considered to be very low. The average test score for all test takers is about 100. In fact, 68 percent of test takers receive a score between 85 and 115. A score of over 140 is considered to indicate that the test taker is gifted with an above-average intelligence.
There are three main types of IQ tests that were created by psychologist David Wechsler. Two tests are designed to gauge the intelligence of children: the Wechsler Intelligence Scale for Children, or WISC, and the Wechsler Preschool and Primary Scale of Intelligence, or WPPSI. There is also an adult version of the test known as the WAIS-IV.