failure:drift

Drift

Drift in the context of production machine-learning systems.

10

Lessons

Formal explanations, examples, simulations, and checkpoints.

Forecasting & temporal ML

Forecast contracts and naive models

A forecast begins with two clocks—when you know and when you predict—and a baseline that respects both.

Forecasting & temporal ML

Trend, seasonality, and known-future signals

A temporal feature is valid only if its value could be reconstructed exactly at the forecast origin.

Forecasting & temporal ML

Backtesting without time travel

A faithful backtest is a replay of past information states, not merely a sorted split.

Forecasting & temporal ML

Statistical and ML forecasters

Choose a forecaster and a multi-step strategy together; the estimator alone does not define the forecast.

Forecasting & temporal ML

Intervals, drift, and forecast operations

Forecast reliability is the joint discipline of calibrated ranges, drift evidence, and a usable fallback.

Reliability, monitoring & experimentation

ML SLIs, SLOs, error budgets, ownership

ML reliability joins immediate system health with delayed decision truth under one owned operating contract.

Reliability, monitoring & experimentation

Observe system, data, prediction, and business

Observability becomes diagnosis only when every layer can be joined by exact version, request, time, and slice.

Reliability, monitoring & experimentation

Diagnose, mitigate, and write postmortems

Mitigate harm quickly, preserve causality carefully, and make the postmortem change the system rather than the story.

Reliability, monitoring & experimentation

Randomized experiments and guardrails

Trust an experiment only after assignment, exposure, unit of analysis, uncertainty, and guardrails all agree.

Reliability, monitoring & experimentation

Drift, retraining, rollback, continuous verification

Continuous verification should automate evidence collection; promotion remains a gated response to demonstrated decision need.