mesure of calibration calibration slope A measure of calibration that is the rate of change in the appropriately transformed value per unit change of the correspondingly transformed predicted value. For calibration of binary outcome variables (0 or 1), the calibration slope is computed from a statistical model where the log odds of the predicted probabilities is a linear function of the empirical frequencies (logistical regression). The transformation is log odds (logit, the link function for a generalized linear model for the expected value of the outcome). For calibration of count outcome variables (0, 1, 2, 3, ...), the calibration slope may be computed from a statistical model where the log of the predicted mean counts is a linear function of the empirical frequencies determined by unique combinations of the covariates. The transformation is log, the link function, of the counts. There are other types of outcome variables for which the calibration slope may be obtained. Slopes further away from 1.0 indicate, at upper and lower values, over- or under-confidence in the prediction. Harold Lehmann, Ken Wilkins, Muhammad Afzal, Joanne Dehnbostel, Khalid Shahin Philippe Rocca-Serra SEVCO group calibration in the small ready for release