What is CLS by PLS
CLS by PLS connects the layout stability of Cumulative Layout Shift (CLS) with how fast the page feels to users — known as Perceived Load Speed (PLS).
PLS reflects user-centric signals, such as how fast the content appears usable, not just when it technically renders. It’s built on real user behavior and data: how soon people start interacting, how often they bounce, how quickly they scroll, and more.
This lens reveals whether your site “feels” stable even when the CLS metric is poor — or vice versa. It helps diagnose where perception and reality don’t match.
Healthy CLS by PLS sample
A healthy chart will show good PLS sessions paired with green CLS values — meaning:
Pages feel fast, and they are visually stable.
Users are satisfied and interact early.
There’s alignment between what the browser renders and how stable the layout feels during load.
This is the ideal state: reality and perception working together.
Unhealthy CLS by PLS sample
The problem arises when:
Good PLS, but poor CLS: This can happen if the page loads quickly, but content jumps or shifts after the user starts interacting. It feels fast, but introduces frustration through instability.
Poor PLS, but good CLS: This might happen if the layout is stable, but slow-loading assets or deferred content cause a lag in perceived readiness. Users might wait too long before they feel like they can engage.
Misalignment here tells you something deeper is off — either in how stability is maintained during fast loads, or in how delays undermine the visual experience.
Resolving unhealthy CLS by PLS
Go-to action plan to resolve an unhealthy CLS by PLS:
Ask Uxi to analyze your CLS by PLS values and suggest improvements
Use Filters to find specific layouts where PLS and CLS diverge, and drill into layout shifts, fixed elements, or DOM injections.
Simulate CLS of the suspected lens to see if fixing it will resolve the CLS by PLS. If yes, this is where the resolution focus should be.
Use an automated CLS optimization tool like Navigation AI to improve your CLS by PLS values
Once you’ve improved CLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
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