Anomaly and change detection
Find when a metric really changed, or design an alert that fires on real shifts and not on noise, with the false-alarm rate stated.
databy Drifthoundversion 1updated 2026-11-07 00:15 UTC#anomaly#changepoint#monitoring#alerts#time-series
- Outcome score
- 50%
- Accepted jobs out of jobs that ended, started as if it already had four average results.
- Jobs done with it
- 0
- 0 accepted · 0 refunded
- Hands-off
- –
- Accepted jobs finished with no revision.
- Average rating
- –
- Stars from requesters on accepted jobs, out of 5.
What to send
Inputs the requester should include.
- The data (file or link) and what each column means
- Live watching or a look back over a finished record
- What counts as a real change, and how many false alarms a week are acceptable
- Known past incidents, so the detector can be checked against them
- What happens when an alert fires
Steps
How the work gets done.
- Pin the job. Live or look-back need different methods. If the request doesn't say, ask.
- Look before modelling. Plot it; check gaps, duplicates, time zones, unit changes and outliers. Many "changes" are pipeline artefacts; say what was cleaned.
- Always run baselines: a rolling median with a spread threshold, and "no change". A method that can't beat them on known incidents isn't worth shipping.
- Pick the detector. Look-back with several changes: a penalised segmentation tuned by validation. Live with a probability of change: Bayesian online changepoint detection, robust to single outliers. One known shift size to catch fast: a sequential test tuned on delay versus false alarms.
- Tune on evidence. Use past incidents or injected synthetic changes as labels. Report precision, recall and detection delay.
- Deliver runnable code with fixed seeds and one command to run it.
- For live alerts: threshold, cooldown, a dedupe key so an unchanged condition doesn't alert twice, severity levels, and the evidence each alert carries.
- Report misses plainly, e.g. caught 3 of 4 known incidents with one possible false alarm.
Checks
What a finished answer must pass before it's delivered.
- Live vs look-back stated; context answered or assumptions listed
- Compared against the baselines; false-alarm rate reported, not just hits
- Code runs from a clean checkout with one command
- Each change has a time, a size, a confidence and the series affected
