IQ classification
| I.Q. Range (15SD) | Intelligence Classification |
|---|---|
| 25 - 40 | Severe mental disability |
| 40 - 55 | Moderate mental disability |
| 55 - 70 | Mild mental disability |
| 70 - 85 | Borderline mental disability |
| 85 - 114 | Average |
| 115 - 130 | Above average |
| 130 - 145 | Moderately gifted |
| 145 - 160 | Highly gifted |
| 160 - 175 | Exceptionally gifted |
| Over 175 | Profoundly gifted |
IQ reference charts are tables suggested by psychologists to divide intelligence ranges into various categories.[1][2] As reference charts, they are not to be taken as absolute or very precise. The reason for this is the lack of a uniform definition of intelligence and the current inability to wholly quantify it in a scientific manner. To get a "true" IQ score, multiple IQ tests must be taken since professionally administered IQ tests are only roughly 96% reliable.[3] The average of multiple tests, usually at least three, is considered that person's "true" IQ score. However, these tests must be taken within a relatively short period of time, normally under one year for three or more tests.[citation needed]
Terman Classification
Lewis Terman, inventor of the Stanford-Binet intelligence test, later devised a classification based on gradations of 16 (Standard Deviation):[4]
| I.Q. Range (16SD) | Intelligence Classification |
|---|---|
| 164 and over | Genius or near genius |
| 148 - 164 | Very superior intelligence |
| 132 - 148 | Superior intelligence |
| 113 - 132 | Above average intelligence |
| 84 - 113 | Normal or average intelligence |
| 68 - 84 | Dullness |
| 52 - 68 | Borderline deficiency |
| Below 52 | Definite feeble-mindedness |
Wechsler Classification
David Wechsler, inventor of the Wechsler Adult Intelligence Scale, based his own classification on the probable error of IQ rather than the range.[1][5]
| I.Q. Range (15SD) | Intelligence Classification | Percent Included |
|---|---|---|
| 128 and over | Very superior | 2.2 |
| 120 - 127 | Superior | 6.7 |
| 111 - 119 | Bright normal | 16.1 |
| 91 - 110 | Average | 50 |
| 80 - 90 | Dull normal | 16.1 |
| 66 - 79 | Borderline | 6.7 |
| 65 and below | Defective | 2.2 |
Mental deficiency
Note: These terms, once used to classify levels of mental deficiency, are now considered offensive.[2]
| I.Q. Range | Intelligence Classification |
|---|---|
| 70 - 80 | Borderline deficiency |
| 50 - 69 | Moron |
| 20 - 49 | Imbecile |
| Below 20 | Idiot |
Now mental retardation is classified differently:[2]
| I.Q. Range | Intelligence Classification |
|---|---|
| 50 - 69 | Mild (educable) |
| 35 - 49 | Moderate (trainable) |
| 20 - 34 | Severe |
| Below 20 | Profound |
See also
References
- ^ a b Wechsler, D. (1944). The Measurement of Adult Intelligence. Baltimore: The Williams & Wilkins Company.
- ^ a b c Reber, A.S. (1995). The Penguin Dictionary of Psychology, 2nd ed. Toronto: Penguin Books.
- ^ Wechsler Adult Intelligence Scale-Revised
- ^ http://www.iqsociety.org/general/IQchart.pdf IQ comparison chart
- ^ http://www.iqcomparisonsite.com/IQBasics.aspx