Google's page experience ranking system evaluates the performance of websites based on their Core Web Vitals metrics, which measure how real users interact with a site. These metrics include Largest Contentful Paint (LCP), First Input Delay (FID), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP). Unlike Lighthouse scores, which are lab-based tests, Core Web Vitals field data is collected from real users browsing the site, providing more accurate insights into user experience. Improving Core Web Vitals can improve user experience, conversion rates, and search ranking, but it's essential to note that internet connectivity and device performance vary globally, and slower regions may impact rankings. Google collects this data on a 28-day sliding window, making it challenging to see the full impact of improvements or regressions immediately. To maximize iteration velocity, tools like Vercel Speed Insights provide real-time, easily filterable access to Core Web Vitals, allowing developers to quickly identify and fix issues as they appear.