Make Your Child Smarter

Difference in IQ Scores

Q: I had my son privately tested when he was in first grade. He scored a 137 on the WISC-IV. His school administered the Test of Cognitive Skills when he was in third grade and he received a score of 124. He said his teacher didn't tell him what that test was for (entry into his school's gifted program) and that it wasn't important; just do it. Could this have affected his score? Which test more accurately shows my child's true abilities? 

A: No two different tests should be compared in terms of the IQ scores, especially at different ages as these tests are age-normed. The Test of Cognitive Skills assesses academic aptitude that includes verbal, nonverbal, and memory skills. It compares achievement levels of students of the same age, grade, and cognitive ability.

Interestingly, sometime back, a study on "The Comparability of the Test of Cognitive Skills with the Wechsler Intelligence Scale for Children-Revised and the Stanford-Binet: Fourth Edition with Gifted Children" indicated Full Scale IQ scores were over 10 points different from their Test of Cognitive Skills (TCS) Cognitive Skills Index. This clearly suggests that there is a limited comparability between TCS and WISC-R and SBIV.

Sometimes, children may not take tests seriously and this may affect the scores to a certain extent, but not to a great extent. Taking a test in a relaxed manner and when stressed may even out the scores depending on the individual. The best thing to do is to approach his teacher to be more familiar with the interpretation of the scores which will enable you to guide him further.

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