Nine Out of Ten Doctors Agree

"Four out of five doctors prefer Camels. The fifth prefers women."

Stock phrase in commercials for non-prescription products with some purported health benefit—especially items which are not actually health care items, such as sugar-free gum.

Sometimes phrased as "Nine out of these ten doctors agree," showing you a group of men in white coats with stethoscopes. This is a clue to what's really going on.

Your brain hears "Nine Out of Ten Doctors Agree", and reads it as "90% of doctors agree." But that's not necessarily what happened—the sample size and population can be anything the advertiser wants it to be, including literally having a panel of only ten doctors asked (and cherrypicking doctors until they get the result they want).

Alternatively, the claim may reflect reality, but what is being claimed isn't the same as what is being sold: listen carefully. Did nine out of ten dentists really say that their brand of toothpaste was best, or did nine out of ten dentists just agree that toothpaste in general is a good idea? Did they say they would recommend this brand over all other brands, or did they just say they would recommend it?

In fact, if you catch wise to the fact that what the nine of ten doctors are agreeing to is something much more generic than what is being sold, you might start to wonder: What's up with the one out of ten doctors who thinks smoking is cool?

As a result, it has in recent years become fashionable for some commercials to poke fun at the trope, implying that the tenth doctor would have endorsed their product, were it not for some external force (he was reaching for the "agree" button when a poisonous snake bit him, sending him into a convulsion before he could agree).

For the classic disassembly of these sort of statistics, may we recommend Darrell Huff's How to Lie with Statistics? The 1950s were a lot less naive than you might assume. And indeed, this is a subtrope of Lies, Damned Lies, and Statistics.

This trope has nothing to do with Doctor Dolittle, Doctor Doom, Doctor Faustus, Doctor Horrible, Doctor Phil, Doctor Slump, Doctor Strange, Dr. Strangelove, Doctor Fate, Doctor Zhivago, Doctor Jekyll, Doctor Steel, witch doctors of any denomination, or any of the Doctors from Doctor Who, though you probably could find something at least nine of them agreed on.

"Tim: Look at this! Nine out of every ten doctors agree that people who don't eat Sunbeam sliced bread will get squashed by elephants! Graeme: That's right. Mind you, it did take us a long time to find the right nine doctors, woo hoo hoo (makes loony signal) ... and the elephants!"
 * The original instance of this phrase comes from Trident gum, where "four out of five dentists recommended sugarless gum for their patients who chew gum". They didn't add the qualifier "if their patients insisted on chewing gum", nor did they tell you that the fifth dentist recommended that his patients not chew gum at all.
 * Years later, Trident would parody this device by having four out of five dentists endorse the gum, with the fifth accidentally denouncing it (being knocked unconscious and landing his face on the "NO" button, having a squirrel crawl up his leg and bite him in the groin, causing him to yell "Nooooooo!" etc.).
 * This was parodied on an early episode of Friends - someone enters and says "Guess what!" and Chandler immediately quips, "The fifth dentist caved, and now they're all recommending Trident?"
 * It was also parodied in a 2004 Corner Gas episode when Wanda admitted that she hadn't seen a dentist since 1992. Brent said, "Well, you should really try to squeeze in a visit every decade or so. Four out of five dentists recommend seeing a dentist. I don't know what the fifth guy's thinking."
 * The legendary Stan Freberg parodied this as far back as the early 1960s with a commercial he made for Chun King Chinese food which proudly proclaimed that nine out of ten doctors recommended the product. The camera then revealed nine smiling Chinese doctors and one scowling Anglo one.
 * An extreme example: an ad for Whiskas claimed that "8 out of 10 Cats prefer Whiskas." This was later changed to "8 out of 10 owners who expressed a preference said that their cats preferred Whiskas." ("who expressed a preference" means there could be twenty thousand cats who'll eat anything for every eight Whiskas lovers, but they don't count.)
 * This is actually gave the name to the Channel4 Panel Show 8 Out Of Ten Cats, which is all about statistics and opinion polls.
 * The Swedish humoristic site Skrattnet used to have a tagline that translates into "Skrattnet, because 20 out of 10 schizophrenics recommend us.".
 * Played with here: "Ten out of nine experts recommend it."
 * Parodied by David Letterman on his talk show, when he claimed that "3 out of 4 Americans make up 75% of the population."
 * This uncyclopedia article, supposing on the answer to what the one out of ten doctors do recommend (leeching and eye of newt for allergy medication and the like..)
 * Parodied when The Goodies go into the advertising business in "It Might As Well Be String".

"Max: (describing what happened to a beat-up gumball machine) A gang of five dentists came through the other night, and four of them just started beating the hell out of it! Sam: What did the fifth one do? Max: He kept sobbing, and saying, "Why can't we all just get along?""
 * Pearls Before Swine had a few comics where Pig introduced his friends, five doctors, four of which agreed on everything, the fifth of which always disagreed. This was for more than just chewing gum—they went to a funeral, and while the first four were offering their condolences, the fifth one just said, "She's dead all right."
 * A strip in Legostar Galactica has this. It turns out that the doctor being talked to is the tenth.
 * Humorous advertising-deconstruction program The Gruen Transfer has actually registered the company "Nine Out Of Ten Experts", and are offering the company's endorsement to products for a "small fee". Nine Out Of Ten Experts recommend The Gruen Transfer.
 * A commercial for Tylenol stated that "9 out of 10 doctors recommend Tylenol!" The very next commercial was for Advil, stating "4 out of 5 doctors prefer Advil!" Humanity is screwed.
 * Those doctors will give you Tylenol but keep all that good Advil for themselves. Duly noted.
 * Now, now, for all you know the 10th/5th doctor just goes "What d'ya got?" After all, it's reasonable to expect you to keep on hand the one that works for you.
 * This invites a lot of questions: are the five Advil doctors part of the Tylenol panel? Did they cherry-pick from the panel? We must know.
 * "Nine out of ten sociopaths agree: You gotta see Hyakugojyuuichi." How's that for meter?
 * Yet another parody, in Sam and Max: Reality 2.0:

""Nine out of ten Americans agree that out of ten Americans, one will disagree with the other nine!""
 * RoboCop The Series has an interesting example, nine out of ten doctors employed by a Mega Corp recommend a drug, clearly in an attempt to invoke the trope.
 * Dying after beaming into a toxic atmosphere in Space Quest V results this quote, "4 out of 5 doctors agree that beaming into a toxic atmosphere without the proper equipment can be hazardous to your health."
 * A variation: speaking of Doctor Who, a wonderful Fun T-Shirt found online has "9 out of 10 Doctors agree, the 10th Doctor should mellow out."
 * Another version: "9 out of 10 doctors agree: Four's scarf is too long."
 * Colin Mochrie on Whose Line Is It Anyway??:

"Tupari Drinks Machine: "Four out of five Tupari drinkers recommend Tupari to their friends. The last one is on my list!""
 * Or how about: "Nine out ten doctors agree the tenth one should really chill out" (did I get that right)
 * On February 15, 2008, a news anchor on Royal Canadian Air Farce said, "A survey shows 51% of Canadians believe there is such a thing as love at first sight. The other 49% are men."
 * A strip of 9 Chickweed Lane showed a group of white-coated figures walking away from another whom they'd apparently just hanged (only his legs are shown, dangling from the top of the panel), and an onlooker remarking, "Nine out of ten doctors agreed."
 * A humorous variant in Mass Effect 2:


 * Played for laughs in Assassin's Creed Brotherhood: a doctor who's treating your bullet wounds will mention that four out of five doctors would use leeches, lucky for you he's the fifth.
 * That`s what happens to the 10th doctor
 * The joke "9 out of 10 people enjoy gang rape". No prizes for guessing who the 10th person is.