15 January 2017

Correlation is not causation








More examples here.  Please share the link, because way WAY too many people do not understand this fundamental principle of science.

5 comments:

  1. This was the very first thing my psychology professor taught us in PSYC 101.

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    1. It's also the first thing many scientists seem to forget when his pet theory get's a low p value.

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  2. Um... you're looking for a correlation coefficient, not a p-value. P-value is say that a result is outside the expected value (such as saying a coin flips heads 5 times in a row -- the p-value of that result is very low, assuming a fair coin). Correlation coefficients are comparing the results of two sets of data, and saying if there is a statistically significant correlation between them. But then, correlation is not causation -- for example, ice cream sales go up with local temperature (people buy more ice cream on hot days). But buying more ice cream will not make the weather warmer.

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    1. Well yes of course. But I don't think it's a random coincidence that ice cream sales go up on hot days like in the examples above.

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  3. My question is: "Why?? did someone choose to look at these correlations in the first place?".

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