Core Web Vitals

Your important questions answered

1. What is the Google Page Experience update? When do I need to take action?

The Page Experience update will introduce brand new mobile focused ranking signals pitching your site against competitors’ sites for mobile friendliness, speed, security and usability.

For many sites, meeting the requirements of this update this will take some work, particularly with more complex investigations around Core Web Vitals.

With the update confirmed to be arriving in Summer 2021, there is only a short amount of time left to get Page Experience up to task and avoid playing catch-up. The time for action is now.

2. Why should I care about Core Web Vitals?

As a ranking factor, fixing Core Web Vitals issues could be the leg-up you’ve been waiting for to gain a competitive advantage.

Core Web Vitals issues can require in-depth analysis and investigation to identify and solve. This means a lot of sites currently have big issues which will begin to affect them in May.

It’s also important to approach Core Web Vitals from a user perspective. Google’s Core Web Vitals report is based on the ChromeUX report, which is composed from an aggregation of user data.

By improving our Core Web Vitals score, we can directly improve user experience so it’s not just a Google factor.

3. What are Core Web Vitals?

Core Web Vitals are a collection of Google Web Vital metrics deemed critical to experience.

Google will be combining Core Web Vital Scores with other page experience metrics (e.g. mobile friendliness and HTTPS) to create a new user experience ranking signal in May 2021.

The Core Web Vitals are: Largest Contentful Paint (LCP), First Input Delay (FID) and Cumulative Layout Shift (CLS).

4. Which Core Web Vital is the most important?

Each Core Web Vital is important in it’s own right. With that being said, the vital most important to a site likely depends on the niche – for example an informational site with no login and little user interaction may not report many issues with input delay (FID).

It’s also worth noting that, depending on implementation, it is also possible that optimisation focused on improving one Vital may benefit another- a crossover more likely to be seen for FID and LCP.

5. How can I improve my Core Web Vitals?

Some of the issues with the highest impact on Core Web Vitals are:

  • Time to first byte
  • Render-blocking resources
  • Resource load times
  • Elements loaded out of order

We keep these in mind when investigating, identifying and documenting the resources specific to our page types, allowing us to gain a micro view of each and create recommendations appropriately. We define a page type as those URLs that follow a specific structure or format. All blog posts would be defined as a single page type, as would all products on an e-commerce site.

6. Why use Blue Array to fix this?

We don’t just offer the investigations, we offer the support and implementation reviews necessary to push success over the line.

Our team of industry leading Technical SEOs have a high level of experience creating in-depth page speed recommendations. We have streamlined that knowledge into our Core Web Vitals Investigation, focusing on areas key to improving these critical metrics.

We focus on creating resources with implementation in mind. We realise that often SEOs and developers have different approaches, which is why we value working with developer feedback to find actionable solutions.

Our presentations are flexible and delivered with our audience in mind, meaning we’ll take the time to explain concepts in more digestible terms, or get right into the core of the issue, depending on who we’re catering to.

Page Experience overview

Google uses the Chrome UX report to aggregate data about page performance. In Google Search Console, pages are grouped first by issue and then by type, helping us identify the page types to focus our attention on.



LCP, or Largest Contentful Paint, is used to identify how quickly important page content loads. It is a measurement (in seconds) of the time it takes for the largest above-the-fold image or text block to be rendered.



FID, or First Input Delay, is used to identify how quickly a page becomes responsive to user interaction. It is a measurement (in milliseconds) of the time between a user first interacting with a page (clicks, taps and key presses, but not zooming or scrolling) and the browser beginning to process the event handlers for that interaction.



CLS, or Content Layout Shift, is used to identify the visual stability of a page (i.e. whether elements are shifted unexpectedly by new elements loading in). It is measured as the product of impact fraction and distance fraction, where impact fraction is the percentage of the viewport covered by the unstable element and distance fraction is the distance the element has moved, relative to the viewport.

Mobile friendliness

Mobile friendliness and avoiding intrusive interstitials (where pop ups cover a significant portion of the screen) are already ranking factors for mobile search and will be bundled into the page experience update in May. With more and more people using mobile devices in favour of desktop we need to ensure that we can fulfil our user experience on all devices.


As a minor ranking factor for quite some time, proper HTTPS usage will be included in May’s Page Experience algorithm. Avoiding common HTTPS issues such as mixed content (where a HTTPS page attempts to load HTTP resources) is key to avoiding this algorithmic penalty.

A quick, one minute video on Google’s Page Experience Update

Summary of offering

Investigation into Core Web Vitals hygiene. Specific recommendations based on page type. Identifying key movers for improving LCP, CLS and FID. Helping to improve customer experience and reduce bounce rate by improving speed, layout shift and interactivity.

See an example

3 Page template types


  • Breakdown of issues by page type
  • Slide-deck reporting findings and recommendations
  • Development backlog
  • Presentation of findings

6 Page template types

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  • Breakdown of issues by page type
  • Slide-deck reporting findings and recommendations
  • Competitor landscape analysis
  • Development backlog
  • Presentation of findings
  • Implementation review and support

7+ Page template types

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