As of December 3, 2020, PageSpeed Insights (PSI) is using the Chrome User Experience Report (CrUX) API
as its source of field data. Previously, PSI was using its own custom data pipeline similar to CrUX, but this change brings the two in closer alignment. In the API, this affects the loadingExperience
objects. Specifically, the values of percentiles
of field data metrics should now be identical across APIs.
Note that PSI users who have been monitoring their metrics over time may have noticed a small jump when the data source of the API was switched over. Most users should not notice any significant changes in their results, but please start a new thread to let us know if you see anything unusual or have any questions.