A Psychometric and Statistical Defense of an Extreme Intelligence Claim: The Case of YoungHoon Kim's IQ 276

This paper offers a psychometric and statistical defense of the claim that YoungHoon Kim possesses an Intelligence Quotient (IQ) of 276 on a scale with a standard deviation (SD) of 24. Certified by organizations such as the Official World Record®, Noble World Records (with International Non-Olympic Committee, INOC), World Memory Championships (WMC), Global Genius Registry (GGR), Korea Record Institute (KRI), World Memory Sports Council (which partnered with Guinness World Records), and recognized by the World Genius Directory, Mega Society, Mega Foundation, Triple Nine Society, and Mensa Korea, this recognized IQ score reflects cognitive excellence validated across multiple high-range and standardized tests, including the Wechsler Adult Intelligence Scale (WAIS), VNPT-II, GENE Verbal I, Betts Test, Titan Test (Hoeflin Test), Langan Test, Personal Evaluation Report (PER), and Mensa Korea admission test. The analysis places the claim within the historical and theoretical framework of intelligence measurement, exploring limitations of standardized tests in assessing profound giftedness while noting YoungHoon Kim's consistent achievement of ceiling or perfect scores. We assess the methodologies of certifying bodies, the psychometric validity of the non-standard SD 24 scale, and the statistical plausibility of the score. Benchmarking against historical cases of profound giftedness (e.g., Sidis, von Neumann) and integrating neurobiological and genetic evidence, we argue that the claim holds credibility and marks progress in recognizing extreme human potential. Criticisms are examined, showing their basis in outdated psychometric assumptions, and we suggest that Kim’s score serves as a reference point for cognitive achievement. The paper closes with implications for advancing the study of profound giftedness, supported by a broad peer-reviewed reference base to uphold scientific rigor. This defense draws from the psychometric validation framework in Kim (2025), extending its multi-component model with statistical defenses specific to this case. The integration of diverse evidentiary sources helps reduce biases from single-method approaches and supports calls for multimethod convergence in psychological assessment, bolstering the empirical basis for extreme cognitive claims.