Read the right benchmarks
Google says there is no single page experience signal. Core Web Vitals contribute to ranking without guaranteeing a top position. Assess these thresholds at the 75th percentile of measured visits, separately for mobile and desktop.
| Metric | Good benchmark | What it measures |
|---|---|---|
| LCP | ≤ 2.5 s | Display of the largest visible content. |
| INP | ≤ 200 ms | Interaction response through the next paint. |
| CLS | ≤ 0.1 | Visual instability; a unitless measure. |
Move from a score to a cause
- Separate field data from lab tests: one Lighthouse run does not summarize every visit.
- Segment by page, device and task. Check coverage and period before comparing values.
- Fix a measured cause such as a late LCP resource, interaction-blocking work or unreserved space, then repeat the affected task.
Preserve what the score cannot measure
Also check keyboard access, forms, error messages, HTTPS and content obstructed by dialogs or ads. Measure task completion and business outcomes separately. A green metric does not prove that payment, an enquiry or reading succeeds.