SEO finding
The lab run looks good but real visitors measure a worse value
SEO Info Severity: Medium
Part of the audit Page speed and Core Web Vitals. Finding id: seo.labFieldDisagree.
What it costs you
A passing lab test hides a problem that visitors and search engines see. Fixing only what the lab shows will not move the field value.
What to do
Make the lab test look like a visitor: other device, other location, with a click or a scroll. Then fix what shows.
What it checks
- Test and visitor speed results differ
How to fix it
Make the lab test match the visitors
- Check which device and location most visitors use (your analytics) and run the lab test with those.
- Add a step that scrolls the page and clicks the main menu or consent button, so shifts and slow interactions can show.
- Compare again. If the lab now shows the problem, fix it as for any lab finding.
How to check: A lab run with the changed settings shows the same problem as the field data, or the field value drops under the limit.
Thresholds
| Name | Default | Meaning |
|---|---|---|
good_lcp_ms | 2500 | Google's 'good' limit for Largest Contentful Paint. |
good_cls | 0.1 | Google's 'good' limit for Cumulative Layout Shift. |
good_inp_ms | 200 | Google's 'good' limit for Interaction to Next Paint. |
How to verify by hand
Field data for the URL (Chrome UX Report); a lab run from another location and device.
What this relies on
The lab device, network and location stand for the visitors, and the lab run does what visitors do.