The evaluation benchmarks used for the lab data are as follows: Lighthouse first takes a video of the page as it loads in the browser and then evaluates the visible progression between the frames. The speed index measures how quickly the content is displayed visually as the website loads. The sixth metric given in the lab data is the Speed Index. Two further values are also provided here: Time to Interactive (TTI), which is the total time it takes for a page to become interactive, after its Total Blocking Time (TBT), the total time during which it was unresponsive. However, these values have different ranges in the lab data. Here, we once again find the categories of “fast”, “average”, and “slow”, as well as the FCP, LCP, and CLS factors. This tool determines how good the website’s performance is by crawling the URL. Google PageSpeed Insights gets its lab data from Lighthouse, which is an open-source tool. CLS: the cumulative layout shift is between 0 and 10%.These field data scores are once again categorized by speed: Cumulative Layout Shift (CLS), which is an unexpected shift in elements on the page while the site is still loading.Largest Contentful Paint (LCP), which measures when the main content of a website is displayed on screen.First Input Delay (FID), which measures the time after which the user can first interact with the website.
First Contentful Paint (FCP), which states how long it takes for the first image or text on the website to be fully rendered.If field data is available for the given website, the evaluation is based on the following scores: