What is the New Google Page Experience Algorithm all about and how do Core Web Vitals play a part?

27th May 2021

What is the New Google Page Experience Algorithm all about and how do Core Web Vitals play a part?

Google is always trying to find new ways of getting the best content to the searcher and their new algorithm - planned to start affecting searches from June onwards - is going to add some new core metrics into the mix. If you own a website and ignore this algorithm update, there's a risk that your site will start to score worse in Google search results, leading to fewer visitors and potentially less income for you. Here, we've tried to summarise the changes Google is making.

Let's get a bit more detail by asking Google!


OK Google, what are Core Web Vitals?

"Hi, Web Vitals is an initiative by Google to provide unified guidance for quality signals that are essential to delivering a great user experience on the web."


The new "Core Web Vitals" are based around speed, responsiveness and the visual stability of a page, which is designed at prioritising sites that have a strong focus on User Experience (UX).


They're doing this for two main reasons:


  1. To increase emphasis on UX. This means that if Google's criteria for a user having a good experience are met, the page rank will be higher than it will be for a page giving a poor user experience.
  2. To make it easier for webmasters to improve the performance and user experience of our websites.


Google has been tracking page load speed and other page attributes (quoted as "page score") to track the effectiveness of conversion for ads for many years. Essentially, they have seen a strong correlation between core vitals and relevant content with the general user engagement of that page, and have applied their findings to this measurement framework.


"53% of people will leave a page if it takes more than 3 seconds to load"

Source: Google


OK Google, what are the three main areas that your update is going to focus on?

"Well, there are three main metrics that will be included in the Core Web Vitals update. They consist of:

  • Largest Contentful Paint (LCP): Measuring loading performance.
  • First Input Delay (FID): Measuring interactivity.
  • Cumulative Layout Shift (CLS): Measuring visual stability."


OK Google, what is Largest Contentful Paint (LCP)?

"Good question! This web vital measures the loading time of the largest element that is on screen when you land on the page."


In other words, how long does it take for the user to see a significant block of content that allows them to understand what the page's content looks like?


The largest elements on most sites are images. Optimising your images (format, size and quality) and using responsive images, especially for mobile devices, will have a big impact on the LCP score. But it's not just images - there are all sorts of other things to think about including server response time, script elements, fonts, and other resources such as videos which can negatively affect this score.


OK Google, what is First Input Delay (FID)?

"So, this measures responsiveness and interactivity. It is the time from when someone interacts (e.g. clicking a button) to when the browser is able to react to that interaction."


We've all visited websites that take so long to load that we've started to hit links or buttons before the page has finished, and we get confused because nothing happens the first time we try. This isn't a good experience for the visitor.


Time to Interactive (TTI) measures the time it takes for a page to be fully interactive.


Reducing the Total Blocking Time (TBT) will increase the FID score. So removing unused scripts and compressing them will increase the score.


OK Google, what is Cumulative Layout Shift (CLS)?

"Hi, this measures visual stability. A layout shift happens when an element changes position."


When, for example, images do not have a height specified the content underneath shifts when the image is eventually loaded and visible to the visitor. To prevent this from happening, make sure image elements are using a width and a height. When dynamic content like a carousel is used, check that the page doesn't jump around while the slides are loaded.


OK Google, how does my website perform against these new metrics?

Google has changed its Pagespeed Insights tool to emphasise the importance of the core web vitals (https://developers.google.com/speed/pagespeed/insights/), so you can measure both mobile and desktop versions of your site. The results have been graded into a percentage and marked red, amber and green, where green is a "pass" and it's a whopping 90% score. If you think mobile traffic is not as important as your desktop, think again. More Google searches are now done on mobile devices than on desktops and this has been seen by Google since 2015! So Google has placed even more emphasis on the "mobile responsiveness" in their page experience ranking.


What does all this mean?

In summary, what Google is doing means more work needs to be done on most websites, but it'll mean noticeable improvements to the way Google provides its search service for a couple of reasons:

When you're searching for something, you don't just get presented with relevant information, you get presented with relevant information on websites that are fast, stable and easy to use.


Website owners who take action to improve their sites should see an improvement in the performance of their site, with higher search rankings and more engaged visitors.

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