Correct. In case studies of a subset of 15 of these kids, he was one of three with a 200+ IQ. What happened to the other two?

"Christopher Otway"'s story is described in the link. "While in Grade 1, Chris was accelerated to work with fifth-grade students for math and sixth-grade students for English. The following year he did math with seventh-grade students ... at the end of his second-grade year Chris made a full grade skip to fourth grade but took math with the eighth grade. By age 12, he was theoretically enrolled in 9th grade but took five subjects (physics, chemistry, English, math, and economics) with 11th-grade students 5 years older than he." Eventually, "He entered university at 16 years 2 months, graduating with Bachelor of Science (First-Class Honours) in computer science and mathematics at age 20. Chris won a scholarship to a major British university and graduated with a Ph.D. in pure math at age 24. Since then, based in London, he works for a worldwide consultancy assisting other companies with financial strategies."

As for "Ian Baker": starting with preschool, "only after his parents had gently informed the teacher that he had just finished reading Charlotte's Web was he permitted to forego reading readiness exercises". In grade 1 and 2, his teacher worked with him to give him stimulating material, ranging up to grade 8 math, and he was in a pull-out program with other gifted children; however, in grade 3, a new principal canceled the pull-out program, and Ian's teacher permitted him to work on a grade 7 math textbook "with no guidance or assistance, and no other children to work with", and Ian lost interest. Ian was bored and miserable in grades 3-4. He switched schools, and partway through grade 5, was given a high-school math teacher mentor, who took him through math up to grade 9. In grade 6, he took 10th grade math, and the following year skipped into grade 8, taking 11th grade math and CS and 10th grade science. In grade 10, he began taking university math. Ian enrolled in university at 17, did a bachelor's degree in "computing systems engineering", graduated at 20, and was in his fourth year of a Ph.D in digital hardware design at 24.

According to the author of the study, "Ian Baker's mathematical ability is certainly on a par with that of Christopher Otway and may well equal that of Adrian Seng [Terence Tao's pseudonym]. Unlike Adrian and Chris, however, his astonishing potential has largely been ignored by the education system ... It is unfortunate that he had to suffer through four years of appalling educational mismanagement." The author also says, "Adrian is the only child of the 15 who believes that he has been permitted to work, at school, at the level of which he is capable."

What was Adrian's educational program? At age 3.5, he tried entering preschool, but couldn't cope with a full school day at that age and left. At age 5 (by which time he had done all of elementary school math in home study), he entered school again. His parents worked with the principal to design a flexible program, in which he was able to progress through two grade levels per year. At age 6.5, he was attending grades 3, 4, 6, and 7 in different subjects. At age 7.5 he attended high school for part of the day, doing grade 11 math; the rest of the day was spent in grades 5 and 6 at the elementary school. At 8 he was doing math, physics, English, and social studies at high school (variously at grade levels 8, 11, and 12). At 8.5, "having informally sat and passed university entrance mathematics", he started taking university math, first in independent study and then guided by a professor; at age 8.75, he stopped attending any elementary school classes, and spent 3/4 of the day at high school, doing sciences in grades 10, 11, and 12, and humanities and "general studies" in grade 8, and 1/4 at university. By age 12 "his studies at university included fourth-year algebra, second-year physics, and second-year computer science". "By age 14, he had passed university entrance examinations in mathematics, physics, chemistry, biology, and English, and completed university courses in areas such as mathematical physics, quantum mechanics, discrete mathematics, linear and abstract algebra, Lebesgue integration, electromagnetic theory, optics, and several areas of computing science."

(source: "Exceptionally Gifted Children", 2nd edition, by Miraca Gross)

It is, shall we say, interesting to imagine what might have been, if all the kids in the study had been afforded such a program.