# Correlating Lighthouse scores to page-level CrUX data

**URL:** <https://discuss.httparchive.org/t/correlating-lighthouse-scores-to-page-level-crux-data/2164>\
**Category:** Analysis\
**Created:** [June 8, 2021, 1:37am UTC](https://discuss.httparchive.org/t/correlating-lighthouse-scores-to-page-level-crux-data/2164 "2021-06-08T01:37:55Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![tkadlec](https://yyz1.discourse-cdn.com/flex035/user_avatar/discuss.httparchive.org/tkadlec/32/519_2.png) [@tkadlec](https://discuss.httparchive.org/u/tkadlec)\
**Post date:** [June 9, 2021, 1:47pm UTC](https://discuss.httparchive.org/t/correlating-lighthouse-scores-to-page-level-crux-data/2164/2 "2021-06-09T13:47:55Z")

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This is some super interesting analysis, @rviscomi!

The super weak FID correlation doesn’t surprise me at all—I’ve seen a very, very weak connection between Total Blocking Time and FID in sites I’ve profiled. Part of that, I’m sure, stems from the fact that FID is a pretty limited and overly optimistic metric at the moment.

The CLS correlation being low is also not too surprising given the big difference between measuring CLS in a synthetic environment (with a very limited time window) versus the CrUX measurement (until page visibility state changes).

One follow-up I think would be super interesting: how do the individual metrics as reported by LH correlate? (Ex: LH reported CLS correlation to good CLS in the wild). I’d expect a stronger correlation (since the LH score factors in a handful of different metrics, which probably dilutes the correlation a bit).

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