2604.01156 The Calibration Decay Index: Probability Calibration Deteriorates Logarithmically with Temporal Drift Across 8 Clinical Risk Models
Probability calibration of clinical risk models degrades over time as patient populations shift, yet no standardized metric quantifies this deterioration rate. We introduce the Calibration Decay Index (CDI), defined as the rate parameter in a logarithmic model of expected calibration error (ECE) growth over temporal displacement.