What is the difference between PageSpeed Insights and actual user experience?

PageSpeed Insights (PSI) is a Google analysis tool that runs synthetic tests in a controlled environment while also displaying field data from the Chrome User Experience Report (CrUX). Synthetic tests (lab data) simulate a standardized network connection and a mid-range device. Actual user experience (field data), on the other hand, reflects how real visitors experience your site, with different devices, network qualities and locations. For a thorough performance analysis, we always examine both datasets, as they provide different perspectives.