The definition was revised in 1961. That revision specified the meaning of the term subaverage general intellectual functioning in a manner that was to have consider- able impact on the field of mental retardation. One standard deviation below the mean on an intelligence test was delineated as the point at which intellectual func- tioning should be considered subnormal (Hebcr, 1961). This specification meant that on an IQ test with a mean of 100 and a standard deviation of 15, any score below 85 would be diagnostic of mental retardation. If the total population was tested and clas- sified on this basis, almost 16% would be diagnosed as having mental retardation. Even higher percentages would be expected to be found in subpopulations where minority status, language factors, or socioeconomic background depresses intelligence test scores. There It used to be 85