Three different aspects of experience
- LCP · main content loading
- INP · interaction to response
- CLS · unexpected layout movement
How it works
Distinguish real-user data from lab checks and investigate slow or unstable elements.
Example
Example: An image with reserved dimensions can reduce text movement during loading.
Common mistakes
Good scores do not guarantee rankings; page usefulness still matters.
How can you check this in practice?
Use real-user data when available and laboratory tests for diagnosis. Good thresholds are LCP ≤2.5 s, INP ≤200 ms and CLS ≤0.1, assessed at the 75th percentile. Examine mobile and desktop separately; one fast test does not represent all visits.
Distinctions and limitations
LCP measures a large visible element appearing, INP responsiveness and CLS unexpected movement. An overall tool score is not a fourth Core Web Vital. Good values do not guarantee rankings or replace useful content.
Field and lab data
Field data aggregates real experiences across devices and connections. Lab tests are controlled diagnostics. After a fix, field reporting can update gradually; insufficient data is not a zero score.
Product-page example
A large product image can affect LCP, a heavy size-selection handler INP, and an image without reserved space CLS. These are three distinct causes requiring different checks.
Official sources
Editorial responsibility: Martin Zhelyazkov · Founder of Z-Consult
Updated: 05/11/2026
For a correction or question: office@z-consult.bg