Sharpness
Sharpness describes how concentrated forecasts are away from 50 percent, independent of whether they are correct.
Definition
Sharpness measures how often your probabilities are meaningfully different from 50 percent. It reflects forecast informativeness, not correctness.
Why it matters
A forecaster can be well calibrated but unhelpful if probabilities are always near 50 percent. Sharpness captures the willingness to make distinctions.
Common pitfalls
Confusing sharpness with accuracy: Sharp forecasts can be wrong if not calibrated.
Overcorrecting: Chasing sharpness can lead to overconfidence.