(1) To estimate relationships (and constant terms) for use in a forecasting model. (See also fit.) Some software programs erroneously use the term *forecast* to mean calibrate. (2) To assess the extent to which estimated probabilities agree with actual probabilities. In that case, calibration curves plot the predicted probability on the *x*-axis and the actual probability on the *y*-axis. A probability assessor is perfectly calibrated when the events or forecasts assigned a probability of X occur X percent of the time for all categories of probabilities assessed.