Posts

Showing posts with the label Nate Silver

Misusing Probability

Nate Silver has been getting some flack for his declaration that Donald Trump had a 2% chance of winning the GOP nomination. One thing to note in Silver's defense: "2% chance" is not "no chance": 2% chance events happen! But the real problem is elsewhere: Silver thinks we can assign "objective" probabilities to one-off events. But to assign a probability to any potential happening in an "objective" way, we have to abstract from the particular circumstances of time and place absolutely everything that cannot be reduced to a number by which we can "objectively" place that potential happening into a class with other, past happenings taken to be "identical" to the potential happening in all relevant features except those differing numbers. (For instance, we will have to turn each presidential candidate into a point in a vector space, where the number of "factors" we choose to include in our analysis are the dimen...

What Are My Chances of Finishing This Blogpost?

See Nate Silver, here : "The Cleveland Cavaliers led for much of Game 1 of the finals against the Golden State Warriors and had a better than 70 percent shot at winning it when LeBron James put the Cavs up by four with 5:08 left to play." Having just finished reviewing a book on Shackle, who largely holds the same view as Mises on case probability *, I find it interesting to ask just what Silver means here. Clearly, Silver is drawing upon a database of results that contains information on how often teams up four in a game with 5:08 to play won that game. Perhaps he has 200 records that match that criterion, and the team up four won 140 of those games. "But so what?" ask Mises and Shackle. The Cavaliers aren't going to play the Warriors 200 times, starting from this identical situation, so they can win 70% of the time. This game won't result in a Schrödinger's cat situation, with the Cavaliers 70% victorious and 30% defeated; no, one team or the o...