Just saw this news online. Note that top 3 are all Asian countries. Probably one factor is that IQ test is after all still a paper-based test that rewards good test-taking skills. IQ test does not really cover all forms of creative and intellectual ability. Also, most likely the effect of early-age tuition has boosted the IQ scores. Since IQ is defined as the ratio of mental age over actual age, if a child learns material (be it math or vocabulary) beyond his age, by definition his/her IQ would be increased, though this does not mean that he is “smarter”.
In Singapore it is now common that a child by age 6 has already mastered the Primary 1 (age 7) syllabus. This achievement alone will give a mental age of 7, versus a actual age of 6, giving an estimated IQ of 7/6×100%=117.
For those gifted students that pass the GEP test (age 9), it is common that they already possess knowledge of Primary 5 (age 11) syllabus, or even Primary 6 (age 12). This translates to an IQ of around 11/9×100=122 to 12/9×100=133.
Joint 1st: Hong Kong and Singapore (108)
2nd: South Korea (106)
Joint 3rd: Japan and China (105)