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What is Google’s Core Web Vitals and why does it matter?

screenshot of pagespeed insights results

May 2021 marks the moment when Google will start taking Core Web Vital scores in account when choosing where a website ranks in search. We explain what this means and why it is important for your website.

What is Core Web Vitals?

Core Web Vitals is the name of a set of metrics that Google will measure as part of its new search algorithm, starting in May 2021. The measurements are mostly to do with speed – because data shows that every fraction of a second counts when it comes to website user appeal. So far there are main 3 aspects of Core Web Vitals, but this is likely to increase in time:

  • Largest Contentful Paint: how long it takes for all the main parts of your web page to load
  • First Input Delay: how long it takes for people to be able to interact with your site (like pressing a button or clicking on the items in your menu bar)
  • Cumulative Layout Shift: how visually stable your site is – for example, do text boxes or images move around as the page loads?

Why is Core Web Vitals being introduced?

Google is a superstar at sifting through millions of websites to give you the best possible answers to your search query. But while its first page search results include websites with very relevant content, sometimes these sites have slow loading speeds or other irritating quirks. No more! From May, Google will rank websites according to usefulness and usability. This will be of particular importance to mobile phone searches, which make up the majority of web users these days.

How does Core Web Vitals affect my website?

In general, Google is fairly mysterious about how its algorithms rank websites in organic search. However, this time it has openly said the Core Web Vitals scores will affect its ranking choices. Even if this effect is only small, it is still an effect and it is something that can be improved. Websites that don’t pay attention to Core Web Vitals may find they slide down the page rankings, even if they had been highly placed before (and conversely, highly useable sites that hadn’t yet made it to Page 1 might find they can move up the ranks).

What can I do?

You can check the Core Web Vitals Score of your site using this free Google tool:

The tab in the top left hand corner lets you flick between your mobile and desktop results. There’s quite a lot of data, but the most important bit is a little way down the page where you will see the ‘Origin Summary’ heading. In this section, Google will tell you if your site has passed or failed the Core Web Vitals assessment (pictured).

screenshot of pagespeed insights results

If you don’t see the Origin Summary, it’s usually because your site hasn’t had enough traffic via Google Chrome in the previous 28 days. It’s not clear how Google rank websites without enough traffic to get a Core Web Vital score, but it is probably worth trying to improve your site – users hate slow websites! Look at the ‘Lab data’ results for Largest Contentful Paint, Time to Interactive and Cumulative Layout Shift scores which Google will have estimated. Anything results in red signify a potential problem. Amber means ‘could be better’.

Be aware the desktop results are usually better than the mobile results, but because most people browse using their phones, it is the mobile results that are the most important. You will also notice the results change from day to day – that’s because they are affected by local networks and the type of device used to access your site, although Google tries to minimise this affect by considering only the majority of users.

Failed the Core Web Vitals test? We are happy to take a look and advise you. There’s no one-size-fits-all solution and things will be a little uncertain over the next few months as the new algorithm becomes standard. But what we do know is that many websites that have occupied the top slots for a while may well lose their much sought-after position unless some development work is done.

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