Can someone Eli5 please.
In: 8
On a day where lots of people were using umbrellas, more people than usual showed up wet at work.
There is a clear correlation between those 2 events (they both occur a lot on the same days) but there is no causation, as umbrellas do not cause you to get wet.
Things which tend to happen together are correlated. They may or may not cause one another, but when one thing happens, the other thing does too. Causation is when one thing is the cause of another thing.
If Bob punches you in the face, your face will hurt. This is both correlation and causation. The punching and the hurting happen at around the same time, so they are correlated. Bob punched you in the face, and it *caused* your face to hurt, so it’s causation as well.
If Bob punches us both in the face, both my face and your face will hurt at the same time. My face hurting and your face hurting are correlated. However, my face hurting didn’t cause your face to hurt, and neither did your face hurting cause my face to hurt, so there is no causation there. When two things are correlated but there’s no causation between them, there’s generally – but not always! – a shared underlying cause. In this case it’s Bob, who really needs to learn to control his anger.
Think of correlation as two things being ASSOCIATED with each other, but not necessarily one causing the other.
For example, shoe size is correlated with age. As one increases, the other does too (to a point anyway). But you would not make a conclusion that having big feet caused one to age! You would however make the conclusion that one’s increasing foot size is ASSOCIATED with growing/aging.
I recently read an article that stated that use of sleeping pills caused symptoms of dementia for many people. It was erroneous because the data showed that there was an association between sleeping pill use and dementia symptoms, but not proof of cause. As it turns out, sleeping poorly (leading to seeking sleeping pill use) could have been the cause of the dementia since it does damage to one’s memory and cognition, but the data would show either of these things to be associated with it.
On a day where lots of people were using umbrellas, more people than usual showed up wet at work.
There is a clear correlation between those 2 events (they both occur a lot on the same days) but there is no causation, as umbrellas do not cause you to get wet.
Correlation and causation are so much fun! As others have said, causation is where something causes the other thing. Correlation is where two things occur.
Human brains leap to conclusions easily and assume a causation when they have a completely unrelated correlation. There is a website, spurious correlations, dedicated to this. [For example, per capita cheese consumption and number of people dying by entanglement in bedsheets.](https://tylervigen.com/view_correlation?id=7) The data says these are correlated. It certain doesn’t say there is a causation. Cause there ain’t. (Probably.)
Every time it rains my basement floods.
Every time it rains my neighbor wears his rain boots.
My basement flooding does not cause my neighbor to wear rain boots. Likewise my neighbor wearing rain boots doesn’t cause my basement to flood. There is no causation between them. But they are correlated, they appear to happen at the same time. In this case there is an underlying cause (the rain) that connects them both. Sometimes that causes is obvious. Sometimes it’s more subtle or indirect. Sometimes there’s no connection at all, it’s just coincidence.
Correlation and causation are so much fun! As others have said, causation is where something causes the other thing. Correlation is where two things occur.
Human brains leap to conclusions easily and assume a causation when they have a completely unrelated correlation. There is a website, spurious correlations, dedicated to this. [For example, per capita cheese consumption and number of people dying by entanglement in bedsheets.](https://tylervigen.com/view_correlation?id=7) The data says these are correlated. It certain doesn’t say there is a causation. Cause there ain’t. (Probably.)
Correlation is a trend where something occurs and you see that hey. This other things tends to occur more or less. But it doesn’t mean that one actually causes this to occur.
My fav example. Correlation between margarine consumption and divorce. The more margarine consumed. The greater the divorce rate. https://www.tylervigen.com/spurious-correlations
Causation on the other hand. If I take 100 people. I believe that putting your hand on a hot stove will cause a burn. I put it to the test. Yes. 100 people burned their hands. And it was caused by the heat from the stove.
That being said, correlations are useful and necessary. We’ll defined variables/covariates and modeling. We can’t always conduct the cause and effect studies. But we can reasonably infer that there is a strong relationship between two (or more) variables.
Every time it rains my basement floods.
Every time it rains my neighbor wears his rain boots.
My basement flooding does not cause my neighbor to wear rain boots. Likewise my neighbor wearing rain boots doesn’t cause my basement to flood. There is no causation between them. But they are correlated, they appear to happen at the same time. In this case there is an underlying cause (the rain) that connects them both. Sometimes that causes is obvious. Sometimes it’s more subtle or indirect. Sometimes there’s no connection at all, it’s just coincidence.
Thank you all, it means what I thought but you all helped break it down in terms I can grasp.
Latest Answers