What Does an IQ Test Really Mean?

In an evaluation for Special Education, the IQ or cognitive testing is only one piece of information that the team will consider when determining whether or not a child needs special education and/or related services. In addition to being considered for eligibility purposes, the IQ/cognitive testing can reveal areas of strength and weakness which can be valuable in educational planning. IDEA requires that multiple measures be used to determine eligibility for special education. The cognitive or IQ testing is examined in combination with the other testing to give an overall picture. It is important to remember that the scores from these tests alone are not an indicator of eligibility or ineligibility. Additionally, determining whether or not there is a disability and what that disability might be, should not be based on a single test. A person may have a high IQ score and still have a disability. Likewise, a person may have a low IQ score and not have a disability. Multiple measures, more information, is necessary to make that determination.

 There are different tests that may be given that provide this information. Although the scoring varies slightly, most use standard scores. Standard scores compensate for different developmental levels by scoring based on norm references. This means that the age and gender of the test subject are taken into account and the scores are compared to others with similar attributes. The standard scores have a mean of 100 with a standard deviation of 15. What this tells you is that anything withing 15 points in either direction of the mean is considered "normal". An IQ score between 85 and 115 is in the normal range. The more standard deviations away from the mean a score is, the more unusual the result. For example, a score of 70 or 130 would both be scores that are not commonly seen. Additionally scores of 145 or 45 would be quite rare.

When reviewing scores from a cognitive test, it is important to pay attention not just to the overall score but also the scores in the sub-tests. A person may have normal scores in all areas but one. That one low area may be nothing to worry about. We all have areas of strength and weakness. For example, a low verbal comprehension score may be compensated for by a higher visual spacial score. However, a significant discrepancy should be looked at a little closer to make that determination. In our previous example, the team may want to consider a speech and language evaluation to rule out or confirm a problem.

 The information in the testing will also give valuable information to a teacher. If a student has difficulty with verbal comprehension, the teacher should try to give the student written information in addition to verbal information. The IQ and cognitive testing can provide valuable information once we know what those numbers mean. It is okay to ask what the sub-tests are and what the student was asked to do. Remember, the goal is to get the whole picture, not just one piece of the puzzle.