Marilyn vos Savant (born August 11, 1946) is an American magazine columnist, author, lecturer and playwright who rose to fame through her listing in the Guinness Book of World Records under "Highest IQ". Since 1986 she has written Ask Marilyn, a Sunday column in Parade magazine in which she solves puzzles and answers questions from readers on a variety of subjects.

Born	Marilyn Mach August 11, 1946 (1946-08-11) (age 62) St. Louis, Missouri, United States
Occupation	Author
Known for	Guinness Records highest IQ
Spouse(s)	Robert Jarvik (1987-present)

Intelligence quotient score

It is generally acknowledged vos Savant has an extremely high intelligence quotient (IQ) score, and she has held memberships with the high-IQ societies, Mensa International and the Prometheus Society. But there is much confusion over the actual value, with data and calculations variously yielding 167+, 186, 218, 228, and 230. Extremely high IQ measurement is an inexact science: high IQs are very difficult to quantify because so few people have IQs at that level, giving rise to the problems associated with small sample sizes; ceiling bumping caused by tests not designed to measure such high IQs; and fat tailing which gives the impression more high IQs exist than predicted by a normal distribution. Moreover, there are general disagreements and controversies over the validity of IQ scoring at any level.

Vos Savant was listed in each edition of the Guinness Book of World Records from 1986 to 1989 as having the "Highest IQ." Because subsequent editions have omitted the category, her column now reports her listing in "Guinness Hall of Fame." Guinness cites Vos Savant's performance on two intelligence tests: the Stanford-Binet and the Mega Test. She was administered the 1937 Stanford-Binet, Second Edition test ten, which obtained ratio IQ scores by dividing the subject's mental age as assessed by the test by chronological age, then multiplying the quotient by 100. Vos Savant says her first test was in September 1956, and measured her ceiling mental age at 22 years and 10 months (22-10+), yielding an IQ of 228. This is the score listed by Guinness and in her books' "about the author" sections, and it is the one she gives in interviews. Sometimes, a rounded value of 230 appears due to the correct use of significant figures.

The 167+ IQ score is derived from school records indicating vos Savant took the Stanford-Binet in March 1957, at 10 years and 8 months, with a mental age 17-10+. However, it is unclear how the recorded chronological age was derived as March is six or seven months from her August birthday. It is also unclear how this record relates to the accounts reported in Guinness and by vos Savant. It is possible she was administered the test twice, as there were two forms of the Stanford-Binet at the time, "Form L" and "Form M".

Although test designer Ronald K. Hoeflin calculated her IQ at 218, this value was informally arrived at by using 10-6+ for chronological age, and 22-11+ for mental age, and thus seemingly has no obvious rationale. The Second Edition Stanford-Binet ceiling was 22 years and 10 months, not 11 months; and a 10 years and 6 months chronological age corresponds to neither the age in accounts by vos Savant's nor the school records cited by Baumgold.

The second test reported by Guinness is the Mega Test, designed by Ronald K. Hoeflin, administered to vos Savant in the mid-1980s as an adult. The Mega Test yields deviation IQ values obtained by multiplying the subjects normalized z-score, or the rarity of the raw test score, by a constant standard deviation, and adding the product to 100. Vos Savant's raw score was 46 out of a possible 48, with 5.4 z-score, and standard deviation of 16, arriving at a 186 IQ in the 99.999997 percentile, with a rarity of 1 in 30 million.

Assertions that vos Savant's IQ has dropped from 228 as a child to 186 as an adult are incorrect as the two numbers represent different types of IQ. Because upper half of the population, ratio IQs seem to follow a log-normal distribution, with a standard deviation of 0.15 for the natural logarithm of the ratio of mental age to chronological age, vos Savant's Stanford-Binet ratio IQ of 228 corresponds to a deviation IQ of 188, and her Mega Test deviation IQ of 186 corresponds to a ratio IQ of 224.

Although vos Savant's IQ scores are among the highest recorded, the more extravagant claims, stating that she is the smartest person in the world and/or was a child prodigy, should be received with skepticism. Vos Savant herself values IQ tests as measurements of a variety of mental abilities, and believes intelligence itself involves so many factors that "attempts to measure it are useless."

Controversial solutions 

Famous columns

The Monty Hall problem

Perhaps the most well known event involving vos Savant began with a question in her 9 September 1990 column:

"Suppose you're on a game show, and you're given the choice of three doors. Behind one door is a car, the others, goats. You pick a door, say #1, and the host, who knows what's behind the doors, opens another door, say #3, which has a goat. He says to you: 'Do you want to pick door #2?' Is it to your advantage to switch your choice of doors?" —Craig F. Whitaker, Columbia, Maryland

This question, named "the Monty Hall problem" because of its similarity to scenarios on game show Let's Make a Deal, existed long before being posed to vos Savant, but was brought to nationwide attention by her column. Vos Savant answered arguing that the selection should be switched to door #2 because it has a 2/3 chance of success, while door #1 has just 1/3. This response provoked letters of thousands of readers, nearly all arguing doors #1 and #2 each have an equal chance of success. A follow-up column reaffirming her position served only to intensify the debate and soon became a feature article on the front page of The New York Times. Among the ranks of dissenting arguments were hundreds of academics and mathematicians excoriating her for propagating innumeracy.

Under the most common interpretation of the problem where the host opens a losing door and offers a switch, vos Savant's answer is correct because her interpretation assumes the host will always avoid the door with the prize. However, having the host opening a door at random, or offering a switch only if the initial choice is correct, is a completely different problem, and is not the question for which she provided a solution. Marilyn addressed these issues by writing the following in Parade Magazine, "...the original answer defines certain conditions, the most significant of which is that the host always opens a losing door on purpose. (There's no way he can always open a losing door by chance!) Anything else is a different question."  In Vos Savant's second followup, she went further into an explanation of her assumptions and reasoning, and called on school teachers to present the problem to each of their classrooms. In her final column on the problem, she announced the results of the more than a thousand school experiments. Nearly 100% of the results concluded that it pays to switch. Of the readers who wrote computer simulations of the problem, about 97% reached the same conclusion. A majority of respondents now agree with her original solution, with half of the published letters declaring the letter writers had changed their minds.

"Two boys" problem

Like the Monty Hall problem, the "two boys" or "second-sibling" problem predates Ask Marilyn, but generated controversy in the column, first appearing there in 1991-92 in the context of baby beagles:

A shopkeeper says she has two new baby beagles to show you, but she doesn't know whether they're male, female, or a pair. You tell her that you want only a male, and she telephones the fellow who's giving them a bath. "Is at least one a male?" she asks him. "Yes!" she informs you with a smile. What is the probability that the other one is a male?
—Stephen I. Geller, Pasadena, California

When vos Savant replied "One out of three" readers wrote to argue that the odds were fifty-fifty. In a follow-up, she defended her answer, observing that "If we could shake a pair of puppies out of a cup the way we do dice, there are four ways they could land", in three of which at least one is male, but in only one of which both are male. See Boy or Girl paradox for solution details.

The problem re-emerged in 1996-97 with two cases juxtaposed:

Say that a woman and a man (who are unrelated) each has two children. We know that at least one of the woman's children is a boy and that the man's oldest child is a boy. Can you explain why the chances that the woman has two boys do not equal the chances that the man has two boys? My algebra teacher insists that the probability is greater that the man has two boys, but I think the chances may be the same. What do you think?

Vos Savant agreed with the algebra teacher, writing that the chances are only 1 out of 3 that the woman has two boys, but 1 out of 2 that the man has two boys. Readers argued for 1 out of 2 in both cases, prompting multiple follow-ups. Finally vos Savant started a survey, calling on women readers with exactly two children and at least one boy to tell her the sex of both children. With almost eighteen thousand responses, the results showed 35.9% (a little over 1 in 3) with two boys.

Publications

• 1985 - Omni I.Q. Quiz Contest
• 1990 - Brain Building: Exercising Yourself Smarter (co-written with Leonore Fleischer)
• 1992 - Ask Marilyn: Answers to America's Most Frequently Asked Questions
• 1993 - The World's Most Famous Math Problem: The Proof of Fermat's Last Theorem and Other Mathematical Mysteries
• 1994 - More Marilyn: Some Like It Bright!
• 1994 - "I've Forgotten Everything I Learned in School!": A Refresher Course to Help You Reclaim Your Education
• 1996 - Of Course I'm for Monogamy: I'm Also for Everlasting Peace and an End to Taxes
• 1996 - The Power of Logical Thinking: Easy Lessons in the Art of Reasoning…and Hard Facts about Its Absence in Our Lives
• 2000 - The Art of Spelling: The Madness and the Method
• 2002 - Growing Up: A Classic American Childhood

In addition to her published works, Marilyn has written a collection of humorous short stories called Short Shorts, a stage play called It Was Poppa's Will, and two novels: a satire of a dozen classical civilizations in history called The Re-Creation, and a futuristic political fantasy, as yet untitled.