# Understanding drift events

> A drift event means a monitored page changed since its baseline. Events are ranked Critical, High, Medium, Low, or Info so you can tell an emergency (schema gone, page returning an error) from a routine edit at a glance.

*Category: Monitoring & Drift · Last updated: 2026-07-07*

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A drift event is SuperSchema telling you that a monitored page is different from its baseline. Each event includes what changed, a before and after view, and a recommended action. Not every change is a problem, so events are ranked by how much they matter. A missing schema block or a page returning an error is urgent. A tweaked meta description usually is not.

### Severity levels

Every drift event carries a severity. This is the fastest way to know whether to act now or just take note. The label and color shown on each event map directly to these levels:

| Severity | Meaning | Typical example |
| --- | --- | --- |
| Critical | The page is broken for AI. Fix right away. | All structured data removed from the page, or the page returning an HTTP error. |
| High | A real problem that misleads AI. Fix soon. | A schema type removed, an identity property changed, pricing removed from a Product, or the page set to noindex. |
| Medium | Worth a look. May need a schema refresh. | Title, meta description, or H1 changed; a price changed; canonical URL changed. |
| Low | Informational. Usually just a heads-up. | Body content changed on its own, author changed, or a published date shifted. |
| Info | Noted, not stored as an open issue. | A brand-new schema type added to the page. |

> **Note:** Info-level changes are logged but do not become open issues you have to clear. Only Critical, High, Medium, and Low changes are stored as drift events that appear in your open list.

### What each detector watches

Each check runs several detectors. Knowing which one fired tells you what actually changed:

**Schema:** Compares the JSON-LD on the page to the baseline. All structured data removed is Critical. A whole schema type removed, or an identity property (@type, name, url, @id) changed, is High. Other property edits are Medium or Low. A newly added type is Info.

**Content:** Watches the page title, meta description, H1 heading, body text, author, and key entities. A title change is High if your schema name or headline still referenced the old title; otherwise it is Medium. Meta and H1 changes are typically Medium; a body-only change is Low.

**Freshness:** Flags stale dates and outdated year references. A title that names a past year while the content is old is High. A page not modified in over six months is Medium. A changed published date is Low.

**Commercial:** Runs on Product, Service, LocalBusiness, and similar types. Pricing or offers removed is High. A price change, availability change, or service area removed is Medium. Ratings removed is Low.

**Access:** Page-level reachability. An HTTP 4xx or 5xx error is Critical. A new redirect or a new noindex directive is High. A new nofollow or a changed canonical URL is Medium.

### The most important event: schema missing

The single most urgent event is "All structured data removed from page." It means the JSON-LD you deployed is no longer on the live page, most often because a republish or template change stripped it. When this happens, AI systems lose the explicit context that told them what your page is about. The recommended action is to re-generate and re-deploy the schema, then verify it is live again.

> **Warning:** A missing schema does not fix itself. If a republish dropped your JSON-LD, re-deploying is the only way to restore it. Marking the event resolved without re-deploying just clears the alert while the page stays bare to AI.

### Alerts for changes you made on purpose

If you edited a monitored page yourself, you may see a drift event confirming exactly the change you made. That is expected. Monitoring cannot tell an accidental edit from a deliberate one, so it reports both. When the change was intentional and the page is correct as it stands, save the current state as the new baseline so future checks treat it as the new normal. See the resolving drift events article for how each choice behaves.

> **Tip:** A run that finds nothing new is a good sign. When a scheduled check matches the baseline again and no new changes are found, any open events left over from a fix you already made are cleared automatically.

## Questions this answers

- What is a drift event?
- What counts as a significant change?
- How serious is a given drift event?
- What do Critical, High, Medium, and Low mean?
- Why did my schema get flagged as missing?
- Why am I getting an alert for something I changed on purpose?
- What is the difference between a schema change and a content change?
- Why do some changes not create an alert?

## Related

- https://superschema.ai/docs/what-monitoring-does
- https://superschema.ai/docs/resolving-drift-events
- https://superschema.ai/docs/monitoring-roster-and-capacity