The purpose of intelligence testing with children.

What is the purpose of intelligence tests in children? They help doctors, teachers and psychologists diagnose numerous learning difficulties such as cognitive deficits, learning disabilities, processing disorders, attention disorders and mental retardation. To accurately identify any of these, the tests should be conducted in conjunction with other psychological evaluations as well as physical testing. Combined, these tests help professionals build strategies best suited to help these children function and progress in learning. An individualized education …

…up in the projects and had very little education will score as high as someone who grew up in "high society" well educated. Just because one doesn't score as high as the other doesn't invalidate the test. A person who takes the test with full intention of doing well will do as well as they can. If they are not mentally or physically ready, then the person invalidates the test, the test doesn't become invalid.