Ever since after the Stanford-Binet measure it hasn't really been an "Intelligence Quotient" as is widely believed.
The reasons are myriad, and far too deep to cover in the context of this post; however, know that there are a great deal of tests that operate on
what's known as a
standard score. I'll assume you have a basic understanding of Probability & Statistics to avoid having to explain too
much.
A standard score is a score that is normally distributed with an x-bar (mean) of 100 and a standard deviation of 15. Three deviations above the mean
is 145 and three deviations below the mean is 55.
Scores
higher than
145 are subject to '
ceiling effect' and are thus not calculated beyond this point because the percentage of
the population that falls in this category is less than 0.15 percent.
Scores
lower than
55 would be notoriously difficult to ascertain due to an unfortunate lack of higher order cognitive and physical
abilities possessed by those individuals who have such "IQs." Furthermore, those are also represented as less than 0.15 percent of the population.
In the bell curve below, a normal distribution, a standard score is represented with 100 at 0 Standard Distributions, which coincides with the line in
the center of the bell curve.
You can plainly see there is no reason to develop resources to "test" individuals beyond these points due to the fact that they are so rare and quite
frankly who would be qualified to judge them? Wouldn't that be a little silly? Most of the guys developing these tests and measures are between 1
and 2 standard deviations above the mean. They have "IQs" of 115-130 and some of your kids are smarter than they are.
That said, an "IQ" score will be required along with a recommendation from a qualified health professional to determine eligibility in
Gifted
Programs as well as determining who should be given access to state health services for those who are experiencing
Mental Retardation.
If a child is tested to have an "IQ" score of
at least 130, the child will be qualified for gifted programs. Unfortunately, there is a
cut off at 130, so if your child tests as 129, there is nothing that can be done, even though there is error in all statistics, due to the lack
of an ability to measure an individual's
True Score. Speak to a qualified health professional if you know someone who is in this
situation.
If a child is tested to have an "IQ" score of
70 or below, the child will be qualified to obtain benefits provided by the government for
those experiencing MR. Unfortunately this is a cut off situation as well, and those who have an IQ of 71-80 and who may legitimately need to have
these services will be excluded based on the raw score. Speak to a qualified health professional if you know someone who is in this situation.
"IQ" tests must be administered properly for the results to be valid.
I cannot state this with enough emphasis. "IQ" scores must be obtained via proper administered tests by qualified test administrators for their
results to be valid.
That said, the internet "IQ" tests are interesting, but there is very little internal consistency or validity to any of the measures presented, and
are often created by people who wouldn't even know what a square root does on their solar powered calculator. (No offense.)
edit on 4/8/11 by
stalphos because: Grammar, style, and punctuation.