As IQ scores rise, IQ tests are periodically renormed, making them harder. Because eligibility for mental retardation (MR) services relies heavily on IQ scores, renormed tests could significantly impact MR placements. In longitudinal IQ records from nine sites, students with borderline and mild MR lost 5.6 points on average when retested on renormed tests and were more likely to be classified MR than peers retested on the same test. (SM)