There are few financial variables more correlated to performance than commitment to a strategy during its lean years—both the amount of performance and the odds of capturing it over a given period of time. The historical odds of making money in U.S. markets are 50/50 over one-day periods, 68% in one-year periods, 88% in 10-year periods, and (so far) 100% in 20-year periods. Anything that keeps you in the game has a quantifiable advantage.
