# minor lame rant: correlation does not imply... **URL:** \ **Category:** The BBQ Pit\ **Created:** [December 23, 2004, 7:04pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361 "2004-12-23T19:04:16Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![smiling\_bandit](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@smiling\_bandit](https://boards.straightdope.com/u/smiling_bandit)\ **Post date:** [December 23, 2004, 7:04pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/1 "2004-12-23T19:04:16Z")
A long time ago in a town far far away, and every place I’ve been since then, I’ve seen this line: “correlation does not imply causation”. And myriad variations thereof. I hate this sentence. Hate it hate it hate. Because it \*does/i] imply causation. Which is, in fact, all it does. It doesn’t prove causation, but it does imply it. It also usually implicates several other things, maybe even reverse causation. Some of these things may be true, some of them may be false. Rarely, all implied things are true or all of them are false. In the former case, the result was blatantly obvious and the scientists just needed to spend some grant money this year. In the latter we either boned the entire study or learned something totally unexpected from the results. Sigh. Sorry about that. Pointless rant. Just an annoying thing people do. I suppose I do it, too. For exmple, I love twisting a normal phrase: “We’ll cross that bridge when we come to it” into this: “I’ll burn that bridge when I come to it.” I think I actually heard that one off Scott Adam’s Dilbert newsletter. I think its funny, and every time I say it, the other person does a quick-double take and them we both have a laugh over it. ---
**Author:** ![matt\_mcl](https://avatars.discourse-cdn.com/v4/letter/m/7ab992/32.png) [@matt\_mcl](https://boards.straightdope.com/u/matt_mcl)\ **Post date:** [December 23, 2004, 7:11pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/2 "2004-12-23T19:11:16Z")
> [@smiling bandit](#): > > I love twisting a normal phrase: “We’ll cross that bridge when we come to it” into this: “I’ll burn that bridge when I come to it.” To every silver lining there is a dark cloud. The Chinese word for “opportunity” is “problem.” ---
**Author:** ![borschevsky](https://avatars.discourse-cdn.com/v4/letter/b/97f17d/32.png) [@borschevsky](https://boards.straightdope.com/u/borschevsky)\ **Post date:** [December 23, 2004, 7:17pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/3 "2004-12-23T19:17:42Z")
> [@smiling bandit](#): > > Because it does imply causation. Which is, in fact, all it does. It doesn’t prove causation, but it does imply it. It depends on how you’re using “imply.” In mathematics, “A implies B” means “If A is true, then B is true,” so under that definition correlation does not imply causation. ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [December 23, 2004, 7:20pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/4 "2004-12-23T19:20:21Z")
I’ve often seen it phrased as “correlation does not equal causation,” which is more clear and more obviously correct. I suspect the version using “imply” might be a corruption of this. ---
**Author:** ![smiling\_bandit](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@smiling\_bandit](https://boards.straightdope.com/u/smiling_bandit)\ **Post date:** [December 23, 2004, 7:43pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/5 "2004-12-23T19:43:55Z")
> [@](#): > > It depends on how you’re using “imply.” In mathematics, “A implies B” means “If A is true, then B is true,” so under that definition correlation does not imply causation. Ah, thanks for clearing that up. 🙂 … … … Nope, still bothers the pee out of me. ---
**Author:** ![Dead\_Badger](https://avatars.discourse-cdn.com/v4/letter/d/848f3c/32.png) [@Dead\_Badger](https://boards.straightdope.com/u/Dead_Badger)\ **Post date:** [December 23, 2004, 7:50pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/6 "2004-12-23T19:50:02Z")
I agree with **Borschevsky** ; correlation does _not_ imply causation. It offers the _possibility_ of causation, sure, but that’s not implication. Apart from anything else, correlation is a reflexive relation, while causation isn’t, so correlation couldn’t _possibly_ imply causation except in a reflexive frame. At best you might say that there’s a 50% chance of causation, given correlation, but that’s still ignoring the possibility that there might simply be a common and unexamined cause for both variables, so it’d mostly be completely wrong. On the other hand, we can be confident that the sentence “correlation does not imply causation” does in fact bother the pee out of you, so perhaps we can compromise on the fact that the correlation between this sentence and your peeing is in fact causative in nature? ---
**Author:** ![Lost\_Horizon](https://avatars.discourse-cdn.com/v4/letter/l/df788c/32.png) [@Lost\_Horizon](https://boards.straightdope.com/u/Lost_Horizon)\ **Post date:** [December 23, 2004, 8:44pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/7 "2004-12-23T20:44:44Z")
Oh, go take a dirt nap off a short pier. ---
**Author:** ![Dead\_Badger](https://avatars.discourse-cdn.com/v4/letter/d/848f3c/32.png) [@Dead\_Badger](https://boards.straightdope.com/u/Dead_Badger)\ **Post date:** [December 23, 2004, 10:29pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/8 "2004-12-23T22:29:35Z")
> [@Dead Badger](#): > > Apart from anything else, correlation is a reflexive relation, while causation isn’t, so correlation couldn’t _possibly_ imply causation except in a reflexive frame. Did I say reflexive? As any fule kno, I meant symmetric. Obviously. ---
**Author:** ![Ghanima](https://avatars.discourse-cdn.com/v4/letter/g/9e8a1a/32.png) [@Ghanima](https://boards.straightdope.com/u/Ghanima)\ **Post date:** [December 23, 2004, 11:44pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/9 "2004-12-23T23:44:04Z")
I know causation is a word, but I’ve always heard that phrase with the word “causality” and so this thread is bugging me like an itchy tag in a shirt you can’t take off. That’s all, I have nothing to contribute to the actual discussion. I just wanted to popp in and say “Correlation does not imply causality.” ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [December 23, 2004, 11:49pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/10 "2004-12-23T23:49:44Z")
I have always heard “Correlation does not equal causation” too which is correct. I have never noticed “equal” being replaced with “imply”. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [December 24, 2004, 2:51am UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/11 "2004-12-24T02:51:22Z")
> [@smiling bandit](#): > > Nope, still bothers the pee out of me. Tough shit. ---
**Author:** ![Homebrew](https://avatars.discourse-cdn.com/v4/letter/h/c89c15/32.png) [@Homebrew](https://boards.straightdope.com/u/Homebrew)\ **Post date:** [December 24, 2004, 5:47am UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/12 "2004-12-24T05:47:16Z")
> [@smiling bandit](#): > > I think I actually heard that one off Scott Adam’s Dilbert newsletter. If so, it was likely ripped off of a Jimmy Buffett song, which was probably ripped off from some other source. **Jimmy Buffett Burn That Bridge From - Riddles In the Sand** \* I’m not saying I’m scared of you But your love is something new When I hold you we’re swaying in the wind Of all the bridges I’ve ever crossed High and lonesome and wild and lost I feel this time I’ll take it to the end We don’t care what the people may say If there’s a price it’s the price we’ll pay Chorus: And we’ll burn that bridge when we come to it Burn that bridge when we come to it Burn that bridge when we come to it Burn it down Burn it down \* ---
**Author:** ![smiling\_bandit](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@smiling\_bandit](https://boards.straightdope.com/u/smiling_bandit)\ **Post date:** [December 24, 2004, 5:09pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/13 "2004-12-24T17:09:56Z")
> [@](#): > > Tough shit. but now I have to pee! Well, I’ll just gurn that toilett when I come to it! ---
**Author:** ![vertizontal](https://avatars.discourse-cdn.com/v4/letter/v/ad7895/32.png) [@vertizontal](https://boards.straightdope.com/u/vertizontal)\ **Post date:** [December 24, 2004, 5:29pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/14 "2004-12-24T17:29:35Z")
> [@smiling bandit](#): > > … I love twisting a normal phrase: “We’ll cross that bridge when we come to it” into this: “I’ll burn that bridge when I come to it.” I think I actually heard that one off Scott Adam’s Dilbert newsletter. I think its funny, and every time I say it, the other person does a quick-double take and them we both have a laugh over it. I usually say “We’ll **drive off** that bridge when we come to it.”, and then the conversation switches into a discussion of Senator Kennedy, for some reason… 😃 ---
**Author:** ![1010011010](https://avatars.discourse-cdn.com/v4/letter/1/ea666f/32.png) [@1010011010](https://boards.straightdope.com/u/1010011010)\ **Post date:** [December 24, 2004, 9:37pm UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/15 "2004-12-24T21:37:21Z")
It’s always been a succinct “correlation is not causation” in my experience. I’ve never heard the “imply” version. ---
**Author:** ![Rilchiam](https://avatars.discourse-cdn.com/v4/letter/r/2bfe46/32.png) [@Rilchiam](https://boards.straightdope.com/u/Rilchiam)\ **Post date:** [December 27, 2004, 4:24am UTC](https://boards.straightdope.com/t/minor-lame-rant-correlation-does-not-imply/281361/16 "2004-12-27T04:24:12Z")
It’s not the principle, it’s the money of the thing.