SEO finding
Real visitors measure a poor Core Web Vital
SEO Error Severity: High
Part of the audit Page speed and Core Web Vitals. Finding id: seo.fieldVitalsPoor.
What it costs you
These are the numbers search engines read from real visits, not from a test run. A quarter of your visitors wait longer than this, or see the page jump.
What to do
Start with the metric named. LCP: make the main image or text appear sooner (server response, image size, priority). INP: shorten the scripts that run when a visitor clicks or types. CLS: reserve space for images, ads and late content.
What it checks
- Real visitors get poor speed scores
How to fix it
Work on the poor metric
- Run the lab test for [url] on [device] (the performance audit of this site) to see what delays the metric named in the finding.
- LCP: see the findings on the main image, server response time and render-blocking files.
- INP: look for long tasks in the scripts that handle clicks and typing, often third-party tags.
- CLS: give images and embeds a width and height, and reserve space for banners that appear late.
- Field data covers the last 28 days, so a fix shows in it only gradually.
How to check: Run this rule again about four weeks after the fix: the metric is no longer above the poor threshold.
Thresholds
| Name | Default | Meaning |
|---|---|---|
poor_lcp_ms | 4000 | LCP at the 75th percentile above this is poor. web.dev: '4 seconds is a reasonable "poor" threshold for Largest Contentful Paint' (https://web.dev/articles/defining-core-web-vitals-thresholds, opened 2026-10-17). |
poor_inp_ms | 500 | INP at the 75th percentile above this is poor. web.dev: 'greater than 500 ms is a reasonable "poor" threshold' (same page). |
poor_cls | 0.25 | CLS at the 75th percentile above this is poor. web.dev: '0.25 is an acceptable "poor" threshold' (same page). |