"In 2006, David Lohman, a psychologist at the University of Iowa, co-authored a paper called 'Gifted Today but Not Tomorrow?' in the Journal for the Education of the Gifted, demonstrating just how labile 'giftedness' is. It notes that only 45 percent of the kids who scored 130 or above on the Stanford-Binet would do so on another, similar IQ test at the same point in time. Combine this with the instability of 4-year-old IQs, and it becomes pretty clear that judgments about giftedness should be an ongoing affair, rather than a fateful determination made at one arbitrary moment in time. I wrote to Lohman and asked what percentage of 4-year-olds who scored 130 or above would do so again as 17-year-olds. He answered with a careful regression analysis: about 25 percent."<p>Most people are surprised that IQ scores can change over time for the same individual. But this is a routine finding of most longitudinal studies of individual IQ. I've gathered other reports of this phenomenon in the psychological literature. For example, young people in the famous Lewis Terman longitudinal Genetic Studies of Genius (initial n=1,444 with n=643 in main study group) when tested at high school age (n=503) were found to have dropped 9 IQ points on average in Stanford-Binet IQ. More than two dozen children dropped by 15 IQ points and six by 25 points or more. Parents of those children reported no changes in their children or even that their children were getting brighter (Shurkin 1992, pp. 89-90). Terman observed a similar drop in IQ scores in his study group upon adult IQ testing (Shurkin 1992, pp. 147-150). Samuel R. Pinneau conducted a thorough review of the Berkeley Growth Study (1928-1946; initial n=61, n after eighteen years =40). Alice Moriarty was a Ph.D. researcher at the Menninger Foundation and describes in her book (1966) a number of case studies of longitudinal observations of children's IQ. She observed several subjects whose childhood IQ varied markedly over the course of childhood, and develops hypotheses about why those IQ changes occurred. Anastasi and Urbina (1997, p. 328) point out that childhood IQ scores are poorest at predicting subsequent IQ scores when taken at preschool age.<p>Anastasi, Anne &#38; Urbina, Susana (1997). Psychological Testing. Upper Saddle River, NJ: Prentice Hall.<p>Moriarty, Alice E. (1966). Constancy and IQ Change: A Clinical View of Relationships between Tested IQ and Personality. Springfield, IL: Charles C. Thomas.<p>Pinneau, Samuel R. (1961). Changes in Intelligence Quotient Infancy to Maturity: New Insights from the Berkeley Growth Study with Implications for the Stanford-Binet Scales and Applications to Professional Practice. Boston: Houghton Mifflin.<p>Shurkin, Joel N. (1992). Terman's Kids: The Groundbreaking Study of How the Gifted Grow Up. Boston: Little, Brown.