I need an assessment of some of the problems of using IQ tests in the education system

The impact of the use of IQ tests and scores in the education system depends on what  such tests and scores being used for.  Generally, I would say, though, that their impact is more negative than positive for a few reasons.

First, IQ tests are frequently used to "track" students, that is place them in at a higher or lower level in a classroom and color what is expected of them.  For example, when I was a little girl, learning how to read, we were placed into different groups. There were the Bluebirds, the Robins, the Canaries, and so on.  Some groups were functioning at a much higher level than others.  And it is likely that these groupings were based on the students' IQ scores. We all knew perfectly well which groups were the better and worse groups, and there was a stigma attached to being placed in the lower groups, a really damaging impact on students, whether they are learning to read or are in a calculus class in high school. This tracking has been going on for years, and historically, it was often based on IQ scores and may very well still be.  In addition to stigmatizing students with this kind of tracking, we are missing the boat, I think, not challenging students who would benefit from challenge or pushing other students harder than they should be pushed.  When we make these kinds of decisions based on one test, we are shortchanging students terribly.  

Second, IQ tests are designed to test just a few limited kinds of intelligence, and they do not account for all the kinds of intelligence there are in the world, all those intelligences that Howard Gardner has been doing research on for many years.  If all we offer are IQ tests, we are missing out completely on ways that students can be nurtured, engaged, and challenged in school.  The IQ test does not measure creativity or mechanical ability, for example.  Why do we value such a limited definition of what intelligence is and then disregard all the other gifts our students bring?  This is clearly a negative impact, if the IQ test is the be-all and end-all of assessing our students' intelligence.  

Third, to the best of my knowledge, IQ tests are not particularly good at predicting much of anything. So, what is their purpose to begin with? If they do not predict happiness or financial success or academic success, why do we bother with them at all?  The impact of their predictive value is nil. 

Fourth, what IQ tests do seem to measure is one's socioeconomic status. Very poor children will turn up with lower IQs, not because they are less intelligent, but because their intelligence has not been nurtured.  They may not eat properly. Their parents might be working too hard to offer them stimulating activities, or, as some studies have demonstrated, to even talk to them as much as middle-class and wealthy parents talk to their children.  Do we really need tests to show which children are not getting everything they are entitled to?  I don't think so. If we were to use IQ tests to show that when children do get everything they need, their IQs go up, that would make some sense,  I think. But their impact on solving the problems poor children experience, in and out of school, does not exist.