Comparison of Test Scores
By Inderbir Kaur Sandhu, Ph.D
Q: I'm writing regarding my son's test results at two different GT schools. His is currently 5 yrs 1 month and will be enrolled in kindergarten in the fall. His scores are as follows:
School #1:
WPPSI-III
Verbal: 29
Performance: 26
Kaufman Test of Educational Achievement: 2nd Edition
Reading: 113
Math: 120
School #2:
Kaufman Brief Intelligence Test 2nd Edition Verbal Reasoning percentile rank: 87 Performance Reasoning percentile rank: 88 Composite Score percentile rank: 92
Woodcock-Johnson Tests of Achievement, 3rd edition Age Equivalency: 5.9 Grade Equivalency: K.5
My questions are:
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Are the test scores from the different schools consistent with one another? One is reported as a percentile rank and one as a score so it is difficult to tell.
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How does this equate to IQ? Is there a way to determine IQ from these scores?
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Do these scores indicate 'giftedness'. My son qualified for both programs, but I'm afraid that term is used loosely in this area. I don't want to enroll him in a program that he is going to be overwhelmed in if he doesn't truly belong there.
Any input you can provide would be greatly appreciated. Thank you for your time.
A: Standardized tests give reliable scores regardless of where the tests are taken due to high objectivity in marking. However, different tests focus on different strength and should not be compared based on the scores alone. It should be compared with the norms of the test, not with another. All the intelligence and achievement tests taken are reliable tests and the scores (with all conditions the same) should be reliable.
The percentile rank of a given value or score indicates the percent of the population that scores below it. So, if it's a percentile rank of 92, that means 92% of the population scores below that (which can also mean that he is in the top 8%). The other score is the standard score.
Most tests including The Kaufman Brief Intelligence Test (KBIT) provide raw scores, scaled scores, and intelligent quotient (IQ) scores. Raw scores are scores expressed in their original form without statistical treatment (such as the number of correct answers on a test). These scores are transformed to the standard scores. A standard score is a derived score as opposed to a raw score. Standard scores are derived scores because they are “derived” from the standard deviation and the mean (average) of the variable in question. Standard scores are superior in many ways to other derived scores such as percentile ranks.
As a rule of thumb, in most intelligence tests, giftedness is recognized as IQ 130 or above, or more than two standard deviations above the norm. There should be an IQ score for the KBIT and the WPPSI - not only the scores indicated. Check with the school. Achievement tests do not provide IQ scores.
The scores on the intelligence test appears on the high side, hence it is possible that your son has met the cut-off point for a gifted program. Furthermore, the admission in a gifted program is rather stringent; hence I believe he must have scored very well to be selected in such a program. The tests are a rather standardized measure to screen children suitable for the program so there should not really be a reason to worry too much; unless you have some concerns that the school may be unaware of. In that case, you would need to speak to someone at the school. For now, I think a gifted program is suited for him; the only choice is between the two schools. Hope the explanation helped and best of luck.
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