Predictive accuracy is substantially improved when blending multiple predictors

From the (NetFlix competition Progress Prize winner) KorBell team's summary paper:

Predictive accuracy is substantially improved when blending multiple predictors. Our experience is that most efforts should be concentrated in deriving substantially different approaches, rather than refining a single technique. Consequently, our solution is an ensemble of many [107] methods.

...
We strongly believe that the success of an ensemble approach depends on the ability of its various predictors to expose different, complementing aspects of the data.

...
However, in hindsight, we would probably drop many of these results, and recompute some in a different way. We believe that far fewer results are really necessary. For example, based on just three results one can breach the RMSE=0.8800 barrier ... [W]e have found that at most 11 results suffice for achieving a blend with above 8% improvement over Cinematch score.