Three Characteristics of Intelligence Tests

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One of the most used ways to determine someone's intelligence, is the intelligence test. This article discusses three charateristics of such tests.

Intelligence Tests

Many different types of tests have been developed to test someone’s intelligence. Most of these tests are used to test analytical intelligence, or the capacity for abstract reasoning and handling new situations. Most of these tests possess three important characteristics:

  • IQ tests are random sample surveys.
  • They possess a certain reliability, and
  • A certain validity.

Random Sample Survey

What actually happens in IQ tests is that the results of a person are compared to the results of a referential group of people of about the same age. The absolute score (how many correct answers are given) is less important than how the person performs relatively to the referential group. To make this comparison, an accurate depiction of the actual age group of the person being tested is highly relevant. In other words, the group has to be representative of the population.

A problem that often occurs in the composition of the representative group is that it contains too many ‘intelligent’ people, as they are more likely to come into contact with psychologists. Furthermore, the norm used in intelligence tests is only valid for about 15 to 20 years, as each generation knows a shift in which questions are solved and not solved.


A second characteristic of an intelligence test is its reliability. This means that the test has to provide consistent results for the same person. There are three types of reliability that can be discerned:

  • Test-retest reliability: when a person is asked to make two similar tests a few weeks apart, he or she should score about the same.
  • Split-test reliability: when comparing one part of the test with another part, the scores should be in each other’s vicinity.
  • Parallel-test reliability: when comparing two different tests of equal difficulty, the scores should be quite similar.


A third characteristic of intelligence tests, is the validity, which means that the test should in fact measure what it claims to measure. There are several types of validity in intelligence tests:

  • Notion validity: the accurateness with which a test measures psychological processes that are specified within a theory. (For example, if a theory claims that children get more intelligent as they grow up, this should be obvious in the results of an intelligence test.)
  • Content validity: the degree to which the questions represent the knowledge domain that is supposed to be measured.
  • Congruent validity: when two or more tests are developed to measure the same thing, they should show a correlation in their results.
  • Criterion validity: a measure to show how well the test score correlates with another skill one is interested in. (For example, the correlation between IQ test results and school results.)
  • Predictive validity: the degree to which a test can be used to predict future behavior. (For example, can an IQ test be used to determine whether someone will succeed in college?)


  • Kaplan, R.M. & Saccuzzo, D.P. (2005). Psychological Testing: Principles, applications and issues. Thomsom Wadsworth.
  • Kaufman, A.S. (2009). IQ Testing 101. Springer Publishing Company.

1 comment

Ron Siojo
Posted on Apr 9, 2011