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I wrote "Correlated: Surprising Connections Between Seemingly Unrelated Things" (http://www.correlated.org http://www.correlated.org), and one of the things I r
by jawns 12y ago
I wrote "Correlated: Surprising Connections Between Seemingly Unrelated Things" (http://www.correlated.org http://www.correlated.org), and one of the things I run into a lot when promoting the book is the "correlation doesn't imply causation" line.
Obviously, the statistics I present in the book and on the website are tongue-in-cheek, but I like to take issue with that line, because typically, people don't fully understand what it means. I use a variation of the line in the OP's post -- that "nothing other than correlation implies causation."
- tel 12y agoI don't like that phrase. While I get what it's going toward, it makes it feel as though some kind of "special" correlation implies causation. Really, correlation is just one part of a package of other things which all together imply causation. http://www.amazon.com/Causality-Reasoning-Inference-Judea-Pearl/dp/0521773628 http://www.amazon.com/Causality-Reasoning-Inference-Judea-Pe...
- erikb 12y agoWhen something implies correlation it doesn't mean there actually is correlation. It just means it might be worth to look deeper into that direction, right? Therefore you need all these different attributes to show a causation exists, but a single one should be enough to imply causation. note: I might actually really confusing my word definitions here, btw.
- tel 12y agoYou can't exactly imply correlation (in simple models) you merely observe it. You can imply causation since it's a theoretical claim, not just an observation. What I meant to say before is that correlation cannot imply causation in and of itself because it is merely an observation—you must also build a framework of causal assumptions within which your observed correlation could have only arisen if there was a causal relationship of interest. That final statement is the "implication" we're all talking about. So, "correlation along with an acceptable and proper set of counterfactual assumptions is capable of imply causation sometimes". Just rolls off the tongue, really.
- micro_cam 12y agoYou're joking right? Uncorrelated things can easily be causal.
- msellout 12y agoCould you please give an example? It may be that he is defining causal more narrowly and correlate more broadly than you are.
- deleted 12y ago[deleted]
- afafsd 12y agoHow about this? Playing soccer causes broken hips, but soccer playing is in fact anti-correlated with broken hip incidence. Why? Because most broken hips occur among extremely old people, who generally don't play soccer. [I'm not sure whether this is actually statistically true, but you get the idea, and I'm sure there's a similar example which actually is true.]
- tonyl7126 12y agoJust because old people tend to break their hips more often than younger people wouldn't necessarily make soccer anti-correlated with hip injuries. In your example, if you compared two groups that are identical, the only difference being one plays soccer and the other doesn't, you'd find a correlation between soccer and broken hips.
- micro_cam 12y agoAnything non linear or multivariate: http://en.wikipedia.org/wiki/Correlation_and_dependence http://en.wikipedia.org/wiki/Correlation_and_dependence Ie unemployment is not correlated with age since both young and old people tend to be unemployed...it is a non-linear relationship.
- kretor 12y agoThe right way to disprove "Nothing other than correlation implies causation." would be to find one causation whose existance we know from something other than causation. But you won't find it. Think about any causation. Now ask yourself why we now that it exists. The answer will always be correlation.