T-calibration in semi-parametric models
Anja Mühlemann, Johanna Ziegel
TL;DR
This note investigates calibration of semi-parametric models for identifiable functionals through the lens of all consistent loss functions. It leverages the Choquet/mixture representation of scoring rules, linking calibration to the existence of a unique parameter $\beta^*$ that minimizes every elementary (or Choquet) loss $L_H$, and defines T-calibrated models via the functional $T$ induced by an identification function $V$. When a single optimal parameter exists, the model is T-calibrated and, under suitable conditions, recovers the targeted function $g(X)$; when multiple Pareto-optimal parameters arise, the paper analyzes their structure and provides explicit examples to illustrate non-uniqueness. The results offer a theoretical framework for understanding calibration under loss-function choice in semi-parametric regression and a diagnostic tool for model misspecification via Pareto sets. Overall, the work clarifies how calibration, loss consistency, and identifiability interact to shape parameter estimation beyond mean-structured models.
Abstract
This note relates the calibration of models to the consistent loss functions for the target functional of the model. We demonstrate that a model is calibrated if and only if there is a parameter value that is optimal under all consistent loss functions.
