I am not well-schooled in testing, though I intend to become better informed about it this year. Anyway, I recently read a post on another site that made an important observation. For those of you who've been told that your child doesn't qualify for something because he's "average," this can be an eye opener. If your child fits into the category of you knowing he needs help but the tests saying he's "average," you may need to bone up on testing and what the scores really mean, just as I do:
"Norm-referenced" achievement tests simply compare the students who took that test to each other, and not to any outside standard. All of the old-time tests are norm-referenced. If you are really interested in mastery of content or skills, then norm-referenced tests just don't make sense. Miniumum competency tests make more sense, so look for those.
Also, many professionals use a 95% confidence interval as a definition of "average". That means that any student scoring in the middle 95% of students is called average. That leaves only the top 2.5% and bottom 2.5% deemed not to be average. This theory says that a student with an IQ of 129 is as "average" as his classmate who has a score of 71. They are considered educationally equivalent.
It's clear that is comes down to what TEST was used and how the results were scored. I don't have any good advice about how to find out what your child's scores REALLY mean except to read up on educational testing and to ask lots and lots of questions of your school district -- preferably in writing way BEFORE an IEP meeting. If scores come out saying something about your child that does not hold water with you, ask for other tests since ALL interventions are based on Present Levels of Performance and THEY are determined through testing. Also, ask that your child's scores be translated into PERCENTILES. If his percentile is below 25% , he is below what is considered to be average (tho certainly anyone below the 35th%ile is LOW average). Of course, this will not work for norm-reference tests because only the kids who TOOK the test are in the score -- not the whole universe of peers.