Momentum Myth

"The home team has turned the tide" ... "The market is going up" ... "The other candidate is closing the gap". People talk as though the physical metaphors of inertia and momentum have reality in all sorts of areas. In most cases, they don't. (OK, if enough speculators believe that there's momentum in price movements they may make them act that way—but only temporarily.) Lots of studies show the lack of correlation between past fluctuations and future ones in sports, markets, etc. It's a human tendency to connect random-walk dots and see patterns. That leads to the illusion of streaks and momentum. Trust the statistics instead!

(cf. NoiseAndPredictability (1999-09-14), Expert Political Judgment (2010-05-13), ...) - ^z - 2010-06-04