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Intelligence Testing in a Snapshot

Updated: Feb 7, 2023

I have quite literally given and interpreted a thousand intelligence tests since 2006. The test I tend to administer the most is the Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V) and the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV).

These are well rounded intelligence tests and I am able to look at not only areas (indexes) of general ability but also cognitive processing.

What does the General Ability Index include?

On the adult test there are two areas, what the test refers to as indexes, that measure general ability. This includes Verbal Comprehension (all things language) and Visual-Spatial (patterns, puzzles.) The child test includes these two areas, plus one called Fluid Reasoning. This can be thought of as detective skills where you use background knowledge and deductive reasoning to analyze a new situation. It tends to incorporate internal dialogue as well as understanding patterns.

What does the Cognitive Processing Index include?

On both the adult and child tests this consists of the indexes called Working Memory and Processing Speed. The adult Working Memory Index includes immediate auditory memory abilities. In more user friendly language this means I would read a string of numbers to you and have you do something with them immediately after and I would read you short problems to solve. The child version includes the numbers and also an immediate visual memory task. This allowes me to see if there is a strength or weakenss in either verbal or visual memory. The Processing Speed Index shows how quickly you can scan and process visual information. It includes a paper and pencil task. The task is meant to be simple, as it is solely looking at speed of processing.

Combining the General Ability and Cognitive Processing gives you the Full Scale Intelligence Quotient. This is often advantageous if there is not a large discrepancy between the 4 or 5 indexes measured.

Nerdy statistics to know:

The majority of the population receives an Intelligent Quotient of 100, which falls in the 50th percentile. A percentile score is not the same as a percent correct on a test, so don’t panic! Likewise if you receive a score of 100 that does not mean you received a perfect A. If you fall at the 50th percentile (smack dab in the middle of the bell curve) you would have performed higher than 50% of the population and lower than 50% of the population. Anywhere between 90-109 is perfectly average with low average going down to 85 and high average going up to 115. Tests vary in how they identify their descriptive categories of average and low average. As you move up the bell curve, the scores go to high average, superior, and very superior. Another score to understand is a scaled score. These describe the individual subtests and tend to be much smaller numbers, with perfectly average being 10.

When I interpret the test I am looking for specific patterns, strengths and weaknesses, and variation within and between the indexes. This is all detailed in the report that you receive at the end of the evaluation.



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