The steady rising of IQ scores over the last century - known as the Flynn effect - causes IQ tests norms to become obsolete over time. To counter this effect, IQ tests are "renormed" (made harder) every 15-20 years by resetting the mean score to 100 to account for the previous gains in IQ scores. But according to new research, such renorming may have unintended consequences, particularly in the area of special education placements for children with borderline or mild mental retardation. …
