Although the human brain accounts for merely 2% of the body mass, life without this organ is impossible to imagine. From remembering events and solving problems to making complex decisions and controlling behavior, the human brain performs a host of functions typically taken for granted. However, the organ’s potential varies from person to person and can be measured using an intelligence quotient test or IQ test—a widely used assessment tool.

What is an IQ test?
An IQ test measures an individual’s cognitive abilities with the intent of evaluating the person’s intellectual potential. Standardized IQ tests not only measure cognitive abilities but also compare one’s results with the normative scores for individuals of that age group. Although the techniques used to derive these scores are similar in most IQ tests, there exist different types of IQ tests, each with its distinct purposes and features.

History of IQ tests

• Renowned English polymath Sir Francis Galton was among the first to study intelligence, assessing its concrete aspects and opening a laboratory to measure its characteristics.
• Later, French psychologist Alfred Binet developed the first modern intelligence test, entailing questions intended to identify children lagging in intellectual faculties compared to others of their age groups.
• German psychologist William Stern refined the testing process by devising a formula to assess one’s mental age, calculated by dividing one’s IQ test score by chronological age and multiplying the result by 100.
• Lewis Madison Terman, a professor of cognitive psychology at Stanford University, redesigned the test for use in the United States and created an IQ test version to be used for adults.

Types of IQ tests
Some of the common types of IQ tests are as follows:

• Stanford-Binet Intelligence Scale
  Lewis Madison Terman developed the Stanford-Binet Intelligence Scale in 1916. The test evaluates five faculties – knowledge, visual-spatial processing, fluid reasoning, quantitative reasoning, and working memory – to gauge the test taker’s intelligence. Each factor carries a pre-defined weightage, and a cumulative score is derived based on the individual’s score in each factor.
• Differential Ability Scales
  Differential Ability Scales (DAS-II) were designed to measure children’s cognitive abilities. The test comprises 63 multiple-choice questions assessing children’s information-processing and problem-solving skills. The test has four forms – preschool, school-age, cognitive battery, and school achievement. Standard IQ scores in the DAS-II range from 30 to 170. The DAS-II is designed for children and adolescents from 2.5 years to 17 years and 11 months of age.
• Universal Nonverbal Intelligence Test
  This test measures intelligence in children and adolescents aged 5 to 17 years and 11 months with verbal and language deficits. The test is also suited to children from all cultural backgrounds. Additionally, this test uses pictures, material objects, designs, etc., to assess a child’s cognitive abilities.
• Weschler Individual Achievement Test
  The Weschler Individual Achievement Test is administered to children, adolescents, and adults and measures listening, speaking, reading, writing, and arithmetic skills. The test is widely used in educational and clinical settings.
• Peabody Individual Achievement Test
  This test assesses intelligence based on six criteria – reading recognition, reading comprehension, general information, mathematics, spelling, and written expression. The test follows a multiple-choice format and is designed to detect learning disabilities.

IQ scoring
The average score on IQ tests is 100. IQ test results are classified into score ranges, with each range representing a certain level of intellectual functioning. An individual with an IQ score of 90 to 109 falls in the “average” IQ range. IQ scores from 110 to 119 are considered above average, while individuals with “superior” IQ have scores ranging from 120 to 129. 

Individuals with IQ scores of 130 or higher are considered exceptionally intelligent. On the other side of the spectrum, test takers with IQ scores from 80 to 89 have below-average IQs, while the range from 70 to 79 is considered “very low.” An IQ score lower than 70 is considered “extremely low” and is a cause for concern.

Reasons to opt for an IQ test

Detection of intellectual disabilities
The IQ tests are reliable techniques for identifying learning disabilities and providing timely interventions to rectify the issue. Children and adults with learning disabilities require additional support and guidance, and IQ tests can pave the way for this process.

Identification of gifted individuals
The test scales can also be used to identify exceptionally intelligent or gifted individuals, typically with IQ scores from 120 to 129 or 130 and above, and provide them with educational and career opportunities to tap their potential.

Understanding one’s strengths and weaknesses
An IQ test not only provides a cumulative intelligence score but also individual scores on different criteria. Such a detailed analysis allows understanding one’s strong aspects and pain areas. Based on these scores, individuals may be provided with guidance on overcoming their weaknesses and building on their strengths.

Determination of the effectiveness of education
Data on education and its effectiveness in enhancing students’ cognitive abilities is essential to understand what changes must be brought about in the education system. Official IQ tests provide information on where students attending school or university stand, which typically reflects the status of education in the country.

Today, with digitization, several verified free IQ tests are available online and provide instant results, facilitating easy access and speeding up the process of seeking the required assistance and support based on such scores.