Understanding the Difference Between Your PSI Score and Core Web Vitals

Google PageSpeed Insights Tool

Google PageSpeed Insights (PSI) is one of the tools that are offered by Google to analyze the speed of a web page both in mobile and desktop views. It consists of a detailed report generated from lab data which shows simulated performance and field data that presents actual performance.

Core Web Vitals (CWV)

Core Web Vitals are a set of performance metrics designed by Google to determine how well a given page works in addressing user experience. The three metrics are based on the field data that implies how your website is seen by real users

Largest Contentful Paint (LCP):

Evaluates how quickly the largest content element loads on the page.

Interaction to Next Paint (INP):

Determines the degree of responsiveness and interaction.

Cumulative Layout Shift (CLS):

Quantifies how much the page layout shifts unexpectedly during user scrolling.

PSI’s Performance Score

Performance Score unit is derived from the lab data that defines performance metrics taken under controlled conditions such as fixed devices and network connection

Lab data, also known as synthesized data, is good to use in measuring and debugging performance issues as it is always consistent and results can easily be reproduced

Connection b/w Your PSI score and Your Core Web Vitals

CWVs are used to measure the website’s real-world user experience, as well as being an official Google ranking factor. If any of the three metrics – LCP, INP, OR CLS – are failed, this indicates that the visitors are having slow loading, slow interactivity or visual continuity issues every time they engage with your website.

This is due to the fact that when your Core Web Vitals performance is poor, the overall performance of your website and user experience will be affected in the following facets:

• Low search engine rankings
• Less conversions
• Higher bounce rates

On the other hand, the PSI Performance score is based on lab data which does not simulate actual user experience. A perfect PSI score does not necessarily lead to good performance. Hence, optimizing Core Web Vitals should be the next step to guarantee exceptional usability and great results.

Note: A perfect figure - 100 PSI score does not necessarily mean a good user experience. Passed Core Web Vitals does.