Core Web Vitals - What are they, and why should you care?

Back in the early to mid ‘90s, when Altavista, Ask Jeeves and Yahoo ruled search, Search Engine Optimisation (SEO) was a fairly simple matter. If you stuffed your site with keywords and backlinks your site should have ranked pretty well. By the end of the ‘90s, Google had firmly established itself as the leading search engine and had made its mission to stamp out hacky/black-hat SEO practices and focus on delivering the right search results based on what will be best for the person instigating the search.

Over the last 20 plus years, the complexity of SEO has significantly changed, but so have the tools available to those of us who do this day in, day out. Just within the suite of free Google tools, we saw tools like Google Analytics launched in 2005, Google Tag Manager in 2012 and Google Data Studio in 2016. Pre-dating all of those was a suite of tools for webmasters that were launched in 2001. This became known as Google Webmaster Central (GWC) in 2006, but is better known as Google Webmaster Tools, the term most commonly used for the tools GWC housed. For those of you new to SEO, you will be forgiven for not recognising the name Google Webmaster Central, as it was rebranded as Google Search Console (GSC) in 2018.

Core Web Vitals

If you are not familiar with Google Search Console, you really should be, (or you should let us do it for you!). It houses a suite of tools that help website managers, content producers and developers ensure that their websites are being ranked as they should. As well as tools for measuring performance and index coverage (how your URLs feature in Google’s search engine) there is also a very useful section on-page experience. This area was added to GSC in 2020 ahead of the page experience update to the Google Algorithm that came into effect in June 2021. Key to that algorithm change was the Core Web Vitals, which gathers anonymised data from real users of your website, keeping track of how your site is performing across three Core Web Vitals; Largest Contentful Pain, First Input Delay and Cumulative Layout Shift.

Largest Contentful Pain (LCP)

The LCP is the measure of how quickly your website loads, and like the rest of the Core Web Vitals is scored Good, Needs Improvement, or Poor.

The aim of every site should be that it takes less than 2s for the majority of its content to be loaded so that its users are not constantly waiting for pages to load. Gone are the days when it was acceptable for a site to load in tens of seconds or longer! At webdna our developers take LCP very seriously so that all of our sites are SEO ready from launch. To do this we optimise our server response times, ensure that all assets load as quickly as possible, Javascript and CSS are minified so that they are lightning fast, and that client side rendering is optimised.

First Input Delay (FID)

FID is the time it takes before your site is interactive. A good score is less than 100ms which also happens to be the time below which the human mind will consider the interaction instantaneous.

In a practical sense, FID is measuring the time between before you can do something on a site like interact with its navigation, open an accordion, sign up to a newsletter field, login to a user section, add a product to your cart etc.

In a practical sense, FID is measuring the time between before you can do something on a site like interact with its navigation, open an accordion, sign up to a newsletter field, login to a user section, add a product to your cart etc.

Cumulative Layout Shift (CLS)

CLS is a pet peeve of mine. It is a measure of how stable your page is as it loads, or to put another way, how many times your content moves as different bits load above or around it. This can be really annoying for a user (you can probably tell that this annoys me when I experience it) and is completely unnecessary. Page elements should be fairly stable as the page loads, so that the button that they are trying to click on does not move as a video block loads further up the page. It is almost entirely possible to remove that type of movement during load by setting the size attributes of different assets before they load and controlling how content is loaded through Eager Loading or Lazy Loading depending on what your site needs.

Like LCP and FID, CLS is measured Good, Needs Improvement and Poor, but unlike the other two is not measured in time, but by scoring two measurements; impact fraction and distance fraction. Impact fraction measures how distracting the movement was to the user and distance fraction measures how far the movement was. The scale is a little counterintuitive with Good being less than 0.1, needs improvement between 0.1 and 0.25 and anything above 0.25 being classed as Poor.

Depending on where your particular skill and interest in SEO lies, you probably have more or less interest in Core Web Vitals, but don’t dismiss them, these measures are key to ensuring that your website is as user-friendly as possible and as a result influences your site's Google ranking. At webdna I am lucky that I have the backup of some really talented developers who ensure that all of our sites perform well for the Core Web Vitals so I can work on the bits of SEO that interest me more like ensuring that we are creating great content for our clients. But I am acutely aware of how important Core Web Vitals are as this becomes a really important part of us onboarding any new clients who have not had the webdna treatment in the development of their sites. Think that sounds like you? Why not get in touch and we can see how we could help you improve your SEO.