Tatyana Deryugina (Twitter: @TDeryugina)

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A random lesson in statistics based on a pet peeve of mine

Posted 29 Jun 16 by arbelos

Search for “What successful people do” and you’ll find dozens of articles and books divulging the secrets. Success could be measured by learning a languagestarting a businesshaving good relationships with peoplebeing happy, etc. Typically, the writers will find some “successful” people and scrutinize their strategies. But what few people realize is that looking at what successful people do is not enough to figure out whether a particular strategy is associated with a higher probability of success. Why? Because you need to (at least) know the rate at which “normal” people employ that strategy!

Let me give you a simple example. Suppose that you read in a book that 80 percent of “successful” people get up at or before 6am every day. 80 percent - that’s a lot! But suppose then I tell you that 80 percent of “normal” people get up at or before 6am every day. All of a sudden, the strategy of getting up at 6am doesn’t look so impressive – it’s just something that all people do. If I tell you that 90 percent of normal people get up at 6am, then it looks like you’re better off sleeping in!

Conversely, just because a strategy is rare among “successful” people doesn’t mean that it’s not a good strategy for success. Let’s go back to the 6am example and say that only 10 percent of successful people get up at or before 6am every day. Is it beneficial to sleep in then? Not if I tell you that only 2 percent of “normal” people get up that early – then successful people are 5 times more likely to get up early than normal ones! So it’s vital to know the rate of a behavior in the “general population” if you want to understand its correlation with “success”.

Of course, I have to end this post with a “correlation-is-not-causation” cautionary tale, as every good scientist should. Suppose I tell you that 90 percent of successful people get up later than 6am (as in the previous example), but only 10 percent of “normal” people do (so success = 9 times more likely to get up later than 6am!). Does this mean sleeping in will bring you good fortune? Absolutely not. It’s very possible (and maybe even likely) that success allows you to “rest on your laurels” and relax, so it’s being successful that causes sleeping in, not the other way around.

Lesson over.


Views : 5469 | Tags: Success, statistics, probability
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