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Making Sense of IQ

Updated: Jan 10, 2019

By Nadia Webb.

IQ tests measure a broad range of problem solving skills. The scores are fairly useful in predicting academic and job performance, as well as physical health and income. However, IQ tests are intrinsically incomplete. “The number” leaves out intellectual courage, creativity, motivation, empathy, sense of humor, curiosity and kindness. If we are defined by our IQ only, then the metric is problematic. After all, the Unabomber was once a gifted child who went on to earn a degree from MIT. He is the poster child for the need to look beyond intelligence.

Given the limitations of IQ, what can it tell us?

Each assessment is a snapshot in time. It gives a sense of how the child is performing at a particular stage of his or her development. The pattern of strengths and weaknesses can tip us off to look for fine motor difficulties, inattention, or hidden talents in shy or quiet children. Despite all of the concern about possible racial bias in IQ testing, the tests are far better at picking out gifted children who don’t fit our preconceptions. If it is WISC-IV versus the 3rd grade teacher, the WISC-IV wins hands down in finding our hidden gifted children. Also, using what we know from our 100 years of test construction, modern IQ tests are carefully constructed to prevent bias and even the appearance of bias.

Quality of the answers is considered as part of the evaluation process, along with speed, diversity of ability, knowledge, perception of nuances in words and ideas, and ability to perceive patterns and overarching concepts. This is often one of the ways you can spot gifted, unmotivated kids and kids who are gifted and learning disabled (2E for “twice exceptional”).

Why are IQ tests less precise with high IQ Children?

An individual’s IQ test result is a sample of demonstrated abilities. A good evaluation should identify if there was any concern about a child putting forth his or her best effort. Even under appropriate testing conditions with full effort, IQ scores remain estimates of ability; it is more accurate to say that we are 90% or 95% certain that the true IQ is within a certain range. Making a distinction between children with measured IQ of 130 or 140 is just silliness. Both children could have the same IQ since the rule of thumb is that the IQ score is really +/- 6 points. There is never a point where we can peer into your soul and find “IQ of 129” floating there.

If you picture the bell curve, it is easier to understand why our IQ tests become less precise for gifted children.

As you travel to the right from average IQ of 100, you can see you are slicing a progressively smaller part of the population as you move further into the realm of gifted. Individuals with an IQ of 130 or above are approximately 2.14% of the population. The IQ tests are designed to make the finest distinctions for most of the children taking the test (the 95% of children who fall between 70 and 130.) We are asking a test to make fine distinctions with a relatively blunt tool when we are looking at the extremes.

Do we need the Stanford Binet LM?

Some individuals claim that the Stanford Binet LM makes finer distinctions at the high end than does the WISC-IV. However, because of the Flynn effect, most children would have a higher score on the LM than on the WISC-IV. (There is no peer-reviewed research indicating that the LM is immune to it.) The most common IQ test, the WISC-IV, has been criticized because the scores are lower; however, using the General Abilities Index (GAI) will factor out much of the motor dexterity component. Most HG (highly gifted) and PG (profoundly gifted) kids, while having exceptional abstract thinking skills, tend to have motor skills which are closer to age level, possibly suppressing their scores on specific subtests. The WISC-IV also includes more questions at the high end of the test to better identify gifted children, making the “ceiling” higher.

Remember that the Full Scale IQ is an average. Like a grade point average, you may have A’s and F’s which make your overall GPA “typical.” Knowing the pattern of strengths and weaknesses is usually the most important piece of information. “The Number” tells you relatively little.

For instructions on calculating the GAI, the publisher has provided a free download.

Nadia Webb is a practicing neuropsychologist, college professor, and step-mom. In her private practice, she assesses and intervenes with neurologically impaired children. The core of her practice has become the assessment of gifted and learning disabled youth. In addition to teaching at a university, Dr. Webb has created in-service training programs, designed systems for coordinating care across agencies, and served on several state and national boards addressing the needs of children. Her work has received honors from the American Medical Association, the Department of Defense, and a personal citation by Governor Jane Hull of Arizona. Dr. Webb is a diplomate in pediatric neuropsychology.

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