What is measured
Lighthouse combines several weighted metrics. The audit stores the observed value and never invents a score when the run is unavailable.
Performance and mobile experience
Lighthouse Performance score
This check uses a laboratory performance summary for one control page.
Pass criterion
The control run is stable and individual metrics do not reveal a material delay or blocked interface.
What to fix
Optimise the specific metrics and repeat measurements under the same conditions after each meaningful change.
Automation limit
A laboratory score varies by device and environment and is not the same as field data from all visitors.
Reference