Lost: One IQ Point Per Year

Several factors combine to undermine our ability to detect the full incidence of highly gifted children in the population: (1) gifted children are not systematically assessed as are mentally retarded children; (2) it is common for gifted children to hide their abilities; (3) IQ tests are not constructed with sufficient difficulty to capture the full range of gifted children's abilities; (4) the tests provide no norms beyond the third or fourth standard deviation; (5) mental ages are no longer provided on current tests, which prevents extrapolating ratio IQs for the highly gifted; (6) scores in the highly gifted range are significantly depressed with each new set of test norms. One of the authors of the Stanford-Binet Revision IV, Elizabeth Hagen, explained in an interview (Silverman, 1986) the constraints faced by test constructors. Their objective is to produce instruments that can adequately appraise the full range of individual differences in a chronological age group from the slowest level of development to the most rapid, but the instruments must be fairly easy to administer within a reasonable amount of time. The compromise is to produce instruments that are most effective for the majority of students. Tasks are eliminated if they are successfully completed by 99.99 percent of an age group or are failed by 99.99 percent of an age group. Items that can only be solved by children in classes for the gifted are purposely exclude