Calibration refers to the accuracy with which one can predict one's own performance.
In the first study child chess players, non-chess playing parents, and statistics students were asked to predict chances of winning chess games against hypothetical opponents. These subjective probabilities were compared to the actual probabilities, based on the Elo rating system. Better players' predictions were better calibrated. Confidence and ratings are negatively correlated, indicating that with lower ratings, players are overconfident. Skilled child players' predictions were better calibrated than any of the adults'.