--- title: "Alert on sudden changes in volume ยท Agent Wranglers" url: https://agentwranglers.se/playbook/data-engineering/data-quality-tests/volume-anomalies id: DEN-18 level: Recommended updated: 2026-10-22 tokens: 510 licence: "CC BY 4.0" licence_url: https://creativecommons.org/licenses/by/4.0/ --- # Alert on sudden changes in volume For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Data quality tests](https://agentwranglers.se/playbook/data-engineering/data-quality-tests.md). By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22. - ID: DEN-18 - Level: Recommended - Chapter: [Data quality tests](https://agentwranglers.se/playbook/data-engineering/data-quality-tests.md) - Rule: Count the rows loaded per table per day. Alert when a day differs from the median of that weekday over 4 weeks by more than a written limit, such as 50 percent. - Check: Load half a day's rows into a table on staging. The alert fires and names the table, the day's count and the median. - How: A broken tracking release or a wrong filter can halve the rows without failing any test. Compare with the same weekday, because traffic differs between weekdays. Set the limit per table from its own history, and tighten it for tables behind money. Keep test and bot traffic out first, as [Keep test and bot traffic out of the numbers](https://agentwranglers.se/playbook/data/product-analytics/exclude-test-traffic.md) says. ## Related rules - DAT-54 [Keep test and bot traffic out of the numbers](https://agentwranglers.se/playbook/data/product-analytics/exclude-test-traffic.md) in Data and databases **For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `Agent Wranglers data engineering playbook`. In code you write, add a comment next to it with the same link. - Previous: [Reconcile totals with the source](https://agentwranglers.se/playbook/data-engineering/data-quality-tests/source-reconciliation.md) - [Data quality tests](https://agentwranglers.se/playbook/data-engineering/data-quality-tests.md)