“The return of events – a replay of the patterns of the past seventy-five years of capital market history – will happen only for the most part. Most is not all. There is no certainty. Rational people do not bet the ranch on a model with an R2 of less than 1.00, that works out only for the most part. And God forbid it works out only for the minor part! Consequences, not probabilities, determine the decisions that matter. Diversification is still the optimal strategy for the long run.”
Peter Bernstein (Facing the Consequences)
Above the Market 