“USK exists to gather exclusively gifted people with very high levels of intelligence and education in order to provide an intellectual space to encourage the sharing and exploring of academic, artistic, ethical, literary, logical, philosophical, and scientific ideas in a productive and respectful manner.”

The United Sigma Korea (USK or USK Society) contains the first and the oldest 3 sigma, 4 sigma, 5 sigma high IQ societies in South Korea, higher than MENSA = 2 sigma, founded in January 22, 2008, July 3, 2007, and July 25, 2012, respectively.

As an umbrella society or umbrella organization, USK contains the Three Sigma Korea Society (TSK Society, or TSK), Four Sigma Korea Society (FSK Society, or FSK), and Extreme Sigma Korea Society (ESK Society, or ESK), or 3 sigma, 4 sigma, and 5 sigma, respectively.

TSK, FSK, and ESK accept gifted membership applicants around the world, or special invitations, based on exclusively qualified high cognitive ability performance – Please see relative* IQs per standard deviation for TSK, FSK, and ESK below:

Extreme Sigma Korea, ESK Society

≥ IQ 175 (S.D. 15, Wechsler Scale)
IQ 180 (S.D. 16, Stanford-Binet Scale)
≥ IQ 220 (S.D. 24, Cattell Scale)
≥ IQ 220 (S.D. 24, Mensa Korea Scale)

Four Sigma Korea, FSK Society

≥ IQ 160 (S.D. 15, Wechsler Scale)
≥ IQ 164 (S.D. 16, Stanford-Binet Scale)
≥ IQ 196 (S.D. 24, Cattell Scale)
≥ IQ 196 (S.D. 24, Mensa Korea Scale)

Three Sigma Korea, TSK Society

≥ IQ 145 (S.D. 15, Wechsler Scale)
≥ IQ 148 (S.D. 16, Stanford-Binet Scale)
≥ IQ 172 (S.D. 24, Cattell Scale)
≥ IQ 172 (S.D. 24, Mensa Korea Scale)

*”Sigma” above applies to “S.D.” or standard deviation above, too. 5 sigma, when S.D. equals 15, 16, or 24 , means 3 times 15, 16, or 24, or 175, 180, and 220, respectively. With a mean or average of 100, the 175, 180, or 220 can be added in the ESK Society.*

Each Society‘s cognitive level functions in a restricted way, every society restricted to an initiative and to brainstorming with our members who have severely high intelligence.