IQ is a problematic measure of intelligence. Many have never been tested, while others have taken the test many times to improve their scores. Still, psychologists consider it the best measurement of intelligence out there.
So who has the highest score?
The World Genius Directory, created by Dr. Jason Betts, is a fluid list of the world's top mind compiled from certified IQ tests sent in by listees. Betts says his site is the definitive ranking.
"Other [IQ] websites had existed, and some still do, but they are based and limited by local constraints, for example, written in Spanish, for Europeans only, only accept their friends' tests, and so on," Betts told us in an email. The directory "has no preferences nor bias, except test quality."
The average score on an IQ test is 100. Most people fall within the 85 to 114 range. Any score over 140 is considered a high IQ. A score over 160 is considered a genius IQ.
If you're wondering, Betts includes himself on the directory. His IQ is 168.
16. Ivan Ivec has an IQ of 169
Ivec specializes in high end IQ tests, competitions and statistics. He's a member of Croatia's MENSA and teaches advanced mathematics.
Ivec has puzzle competitions and other tests of academic strength on his website.
15. Gaetano Morelli has an IQ of 169
Gaetano, called "Tany" for short, is an engineer at an Italian firm and the author of a book about Albert Einstein's Theory of Relativity.
He's a member of at least 20 high IQ societies and founded his own, the STHIQ.
His hobbies include bridge, chess and fishing.
14. Jorge del Fresno Viejo has an IQ of 170
Jorge is a member of several IQ societies including Morelli's STHIQ society, the Universal Genius Society and Epida.
(Photo not available.)
13. Mick Dempsey has an IQ of 171
Dempsey has a degree in forensic psychology from London Metropolitan University. He is a youth support worker at Hertfordshire County Council, according to his LinkedIn profile.
Dempsey also enjoys jazz, Faulkner, the Everton soccer club and films including Pulp Fiction, according to his Facebook page.
12. Marc Nydegger has an IQ 171
The 20-year-old prodigy from Fribourg, Switzerland is a scientist and video game designer, according to his profile at Hall of the Ancients.
The profile says his favorite food is "knowledge" and his favorite drink is "intelligence."
11. Santanu Sengupta has an IQ of 174
Sengupta holds an an MBA and bachelor's in Aerospace engineering.
When he's not working the equity property desk for a financial services firm, the 34-year-old enjoys traveling, stimulating discussions, solving puzzles and good food. Sengupta's favorite drink, by the way, is vodka.
10. Vedran Glisic has an IQ of 175
Gilsic, who hails from Bosnia and Herzegovinia, enjoys experimental music, mathematics and chess compositions.
You can check out some his own mixes on ReverbNation.
9. Peter Rodgers has an IQ of 175
The 58-year-old author, physicist and poet has written more than 3,000 poems and published books on emotion, schizophrenia and Albert Einstein.
Rodgers, who earned his bachelor's in Mathematics at the University of Queensland, suffers from dyslexia and epilepsy, but still managed to do well in school.
The poetic genius also hosts his own YouTube channel where he posts creative videos of his poems, music and information on his books.
8. Tadayuki Konno has an IQ of 176
Konno, 39, currently lives in Sakata-shi, Yamagata, Japan. The self-described visionary lists his hobbies on his Facebook page as "making kaibun (Japanese Palindrome), listening to music, watching movies, reading manga comics and novels."
He is a member of the Mysterium Society and the HELLIQ Society.
7. Lee HanKyung has an IQ of 177
Nationality: South Korean
Lee Hankyung, from Daejon, South Korea, is currently a medical student. The 27-year-old is a member of at least five high IQ societies, including Mensa Korea and OLYMPIQ High IQ Society.
6. Tim Roberts has an IQ of 178
Roberts is a professor and the head of the computer science department at Central Queensland University in Australia. His favorite subjects to teach include operating systems, artificial intelligence, and programming.
Before turning to teaching, Roberts worked as a software consultant.
5. Patrick Zimmerschied has an IQ of 178
The 30-year-old currently studies philosophy and political science at the Darmstadt University of Technology, after dropping out of school at age 18.
He has written books and enjoys writing poetry in his spare time.
4. Kenneth Ferrell has an IQ of 190
Ferrell is a practicing physician in Charlotte, N.C. He is a member of various elite IQ societies, including the Epimethius Society and the Order of Imhotep.
The 52-year-old told us that "IQ tests" have become a fun hobby for him over the last five years and he even created verbal and numerical IQ tests of his own: QUINTIQ and 12354.
3. Mislav Predavec has an IQ of 192
Currently a math professor in Croatia's capital of Zagreb, the 45-year-old is also an owner and director of a small trade company.
Predavec is the founder and president of the elite GenerIQ society, which lists Ivec and Ferrell as members.
His Facebook page mentions that he liked Pink Floyd, Mafia Wars, Leonardo Di Vinci and Gloria magazine.
2. Rick Rosner has an IQ of 192
The world's second smartest man is one of the more colorful characters on the list. He has written for various TV shows, was a contestant on "Who Want To Be A Millionaire," and spent many years as a bar bouncer, stripper and nude model.
The 54-year-old, who currently lives in Los Angeles, recently told The Daily that he sometimes stays up 20 hours a day to finish IQ tests in a bid to knock his Greek competitor out of the top spot.
1. Dr. Evangelos Katsioulis has an IQ of 198
The smartest man in the world is a Greek psychiatrist who also holds degrees in philosophy, medical research technology and psychopharmacology.
Katsioulis, 36, also enjoys painting, swimming and traveling.