Saved in:
Bibliographic Details
Main Author: Farran, Tristan
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.13156
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917339020132352
author Farran, Tristan
author_facet Farran, Tristan
contents Practitioners monitoring deployed probabilistic models face a fundamental trap: any fixed-sample test applied repeatedly over an unbounded stream will eventually raise a false alarm, even when the model remains perfectly stable. Existing methods typically lack formal error guarantees, conflate alarm time with changepoint location, and monitor indirect signals that do not fully characterize calibration. We present PITMonitor, an anytime-valid calibration-specific monitor that detects distributional shifts in probability integral transforms via a mixture e-process, providing Type I error control over an unbounded monitoring horizon as well as Bayesian changepoint estimation. On river's FriedmanDrift benchmark, PITMonitor achieves detection rates competitive with the strongest baselines across all three scenarios, although detection delay is substantially longer under local drift.
format Preprint
id arxiv_https___arxiv_org_abs_2603_13156
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle When Your Model Stops Working: Anytime-Valid Calibration Monitoring
Farran, Tristan
Methodology
Machine Learning
62L10 (Primary), 62G10 (Secondary)
Practitioners monitoring deployed probabilistic models face a fundamental trap: any fixed-sample test applied repeatedly over an unbounded stream will eventually raise a false alarm, even when the model remains perfectly stable. Existing methods typically lack formal error guarantees, conflate alarm time with changepoint location, and monitor indirect signals that do not fully characterize calibration. We present PITMonitor, an anytime-valid calibration-specific monitor that detects distributional shifts in probability integral transforms via a mixture e-process, providing Type I error control over an unbounded monitoring horizon as well as Bayesian changepoint estimation. On river's FriedmanDrift benchmark, PITMonitor achieves detection rates competitive with the strongest baselines across all three scenarios, although detection delay is substantially longer under local drift.
title When Your Model Stops Working: Anytime-Valid Calibration Monitoring
topic Methodology
Machine Learning
62L10 (Primary), 62G10 (Secondary)
url https://arxiv.org/abs/2603.13156