What’s Your IQ?

The mystique of the IQ score is alive and well in our culture. One can find all sorts of quizzes on the internet that claim to estimate IQ, but in reality, they are merely games and in no way provide valid IQ scores. Why? IQ tests are legally protected, and with few exceptions (e.g. school psychologists within the educational system) they are only available for use by licensed psychologists who have the proper training in cognitive assessment.

I do not believe that an estimate of any person’s intelligence can be reduced to a number or set of numbers.  IQ tests measure a fairly narrow range of human abilities.

IQ scores, when not properly interpreted, can be dangerous beasts. For example, a Full Scale IQ score, when touted as someone’s *true* intelligence level may mask that person’s potential. This is especially true in cases of learning disorders, as the disorder often negatively impacts performance.  Although most people exhibit strengths and weaknesses on IQ tests, those with learning disorders often exhibit an atypical pattern of performance (either by highly variable scores across individual subtests or by highly variable scores across index or domain scores).  IQ tests, when improperly interpreted, may then be measuring achievement rather than ability level; this is the opposite of what they’re meant to do.

IQ tests are blunt instruments.  That is, by themselves they cannot identify specific processing problems. This is doubly true for achievment tests (such as the Woodcock Johnson and the WIAT-II, amongst many others). The purpose of an IQ test is to identify intellectual level of functioning; the purpose of achievement tests is to measure academic achievement. Even when properly administered and interpreted, the combination of results from an IQ test and an achievement test together merely indicate that there is a discrepancy (or not) between the person’s alleged “innate” ability (IQ) and academic achievement  (what they learned in school).  The “cause” of any discrepancy cannot be ascertained and remains to be discovered.  Neuropsychological evaluation is an excellent way to discover specific processing deficits, as well as obtain diagnosis.

IQ scores can be used to ascertain “giftedness” and are often used for membership in certain groups (e.g. MENSA or school GATE programs). MENSA requires proof that one’s IQ is 130+ from an individually administered IQ test (or other measure with sound psychometric properties such as GRE scores). If you request a “giftedness” evaluation for your child through your school district, however, they will likely use their own abbreviated or group cognitive measure and will not employ a psychologist to administer a full-battery IQ test. Sometimes school districts require high academic achievement, thus those gifted individuals with learning disabilities will often be overlooked for GATE programs. Requirements seem to vary from district to district. The less reliable and valid the instrument that defines such a group’s membership is, the more arbitrary membership in that group becomes. 

The average IQ score of the American public is 100, and the “average range” is between 86 and 114. Most people (almost 70%!) fall into this range.  Another 27% have IQs that are either 1 to 2 standard deviations above (115-129) or 1 to 2 standard deviations below (70-85) the average range. Getting further out there on “tails” of the bell curve, only about 2% of the population has an IQ that is 2 or more standard deviations above the mean (130+).  This is considered the “gifted” range. (If “real” IQ tests are used at all, the cutoff for GATE programs are usually lower.  To experts, though, an IQ of 130+ is unquestionably in the “gifted” range).   Likewise, only about 2% of the population has an IQ that is 2 or more standard deviations below the mean (69 or less).

Additionally, “real” IQ tests cannot accurately estimate very high (140+) IQ scores. Those who claim to have extremely high IQ scores most likely obtained such figures from the internet or from wishful thinking!

I perform IQ evaluations for both adults and children. These assessments include test administration, scoring, and a written report.  The administration portion of the assessment usually takes between 1.5 – 2.5 hours, depending on factors such as evaluatee age.

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Further Reading: What is the difference between a Psychologist, a Neuropsychologist, a Licensed Educational “Psychologist,” and a School “Psychologist?”
The What & Why of Psychological Assessment
Neuropsychology questions
Special education questions 
 What Is Psychotherapy?
Dr. Moleski, Neuropsychologist