Core Web Vitals<\/h2>\n
Google will be using a selection of user-centric metrics, Core Web Vitals, to measure the quality of the user experience. These include the speed, responsiveness, and visual stability of a page. The metrics are:<\/p>\n
- \n
- Largest Contentful Paint<\/a> – how quickly does the first above-the-fold content appear in the browser viewport? This is the perceived load speed (Largest Contentful Paint)?<\/li>\n
- First Input Delay<\/a> – how quickly does the site take to become interactive?<\/li>\n
- Cumulative Layout Shift<\/a> – how stable are the visual elements or do they shift around when interacting or loading potentially causing you to click the wrong thing?<\/li>\n<\/ul>\n
How we’re doing at the moment<\/h2>\n
These are our performance results using Google PageSpeed<\/a>.<\/p>\n
Its data set is based on a combination of field data (data they’ve already collected over the past 28-days) and ‘lab data’ (data that they’re testing at that moment).<\/p>\n
I’ve used the homepage as it represents an example of a regular showcase page, but a sample of different pages need to be tested.<\/p>\n
Some of the performance issues on the homepage are likely to be global elements that may affect all pages.<\/p>\n
For the homepage, desktop and mobile pass the Core Web Vitals test.<\/p>\n
Desktop<\/h3>\n
We perform quite well on desktop.<\/p>\n
- \n
- Largest Contentful Paint – 1.9 seconds is a ‘good’ rating.<\/li>\n
- First Input Delay – 5 milliseconds is a ‘good’ rating.<\/li>\n
- Cumulative Layout Shift – 0 is a ‘good’ rating.<\/li>\n<\/ul>\n
![\"\"](\"https:\/\/blogs.kent.ac.uk\/webdev\/files\/2021\/05\/performance-desktop.jpg\")
<\/a><\/p>\n<\/p>\n
Mobile<\/h3>\n
We pass the Core Web Vitals with a ‘good’ rating, but there are performance improvements to consider.<\/p>\n
- \n
- Largest Contentful Paint – 1.9 seconds is a ‘good’ rating.<\/li>\n
- First Input Delay – 29 milliseconds is a ‘good’ rating.<\/li>\n
- Cumulative Layout Shift – 0 is a ‘good’ rating.<\/li>\n<\/ul>\n
Third-party code is one area that we’re penalised on. This is often used for things like our our chat, youtube, social media and analytics.<\/p>\n
- First Input Delay<\/a> – how quickly does the site take to become interactive?<\/li>\n
![\"\"](\"https:\/\/blogs.kent.ac.uk\/webdev\/files\/2021\/05\/performance-mobile2.jpg\")
<\/a><\/p>\n