“A forecaster who doesn’t adjust her views in light of new information won’t capture the value of that information, while a forecaster who is so impressed by the new information that he bases his forecast entirely on it will lose the value of the old information that underpinned his prior forecast. But the forecaster who carefully balances old and new captures the value in both—and puts it into her new forecast. The best way to do that is by updating often but bit by bit.”