Monday, April 04, 2011

Interesting Failure of Wisdom of Crowds

Like many others, my NCAA bracket went terribly awry this year and I have no teams in the Final Four. However, it did make me think that this is a really interesting failure of wisdom of crowds. According to ESPN:

More than 5.9 million brackets were filled out for's Tournament Challenge, but exactly two went 4-for-4 in picking Final Four teams.

Only 1,093 brackets had three of the Final Four correct, while 2.1 percent had two right. A total of 27.6 percent had one Final Four team, while the vast majority of you -- 70.3 percent -- don't have a single team left.


d said...

There are essentially 26 correct decisions needed to get final 4 correct; 6 correct decisions to get any team in.

By chance, I'd expect to see (roughly) 4*1/64 of the population get one of them right: and people did MUCH better than that.

2*26 is 6.7 million, so we'd expect about one person to get all 26, assuming chance. It's remarkably close!

In other words, my interpretation is that the 'easiest' part of the bracket is more likely than chance--people kind of know who is going to win UNC vs Long Island--but the hard part is pretty much chance.

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