Interviews, insight & analysis on digital media & marketing

Core web vitals – the pillars of user experience success

By Radek Kowalski, Head of Search at McCann Manchester 

When shopping online, nearly half of consumers expect a website to load in less than two seconds, with 40% abandoning a web page that takes longer than three seconds to load. A prolific problem when users are on mobile devices.

To emphasise the scale of these implications, Amazon has quoted that for every 100ms of latency, it loses 1% in sales*. Google has found that an extra 0.5 seconds in search page generation time drops traffic by 20%. This means a broker could lose $4 million in revenue per millisecond if their electronic trading platform is 5 milliseconds behind the competition.

In this article, I’ll look at how Google pursues quality user experience metrics via its Core Web Vitals methodology introduced this month and how optimising third-party resources and tags can help to secure faster page load speeds, CWV (Core Web Vitals) score improvements and, of course, enhance user experience for a website.

What are Core Web Vitals?

Core Web Vitals (CWV) are Google’s latest measurement tool for user experience.

Each of the CWV represents a distinct element of user experience. They are measurable in the ‘field’, which reflects the real-world experience of a user and are undoubtedly the most important ranking factor for 2021.

At present, there are three aspects of CWV user experience — loading, interactivity and visual stability — which include the following metrics:

  • Page Load Performance measured by Largest Contentful Paint (LCP)
  • Interactivity measured by First Input Delay (FID)
  • Visual Stability measured by Cumulative Layout Shift (CLS)

How to Explore Core Web Vitals Data in Google Search Console

The Core Web Vitals report in Google Search Console (GSC) is specifically designed to help webmasters fix poor user experience issues. This report shows how pages perform based on real world usage data, also called ’field data’. Field data is gathered using a CrUX database from actual users visiting pages in real time. You can find this report within the ‘Performance’ section of GSC. Currently, GSC operates on a three-level system of assessment, namely; ‘poor’, ’needs improvement’ and ’good’, all applied to a URL on specific device types.

Google offers a way of validating issues that takes the webmaster through a 28-day monitoring cycle. When a specific issue is fixed by developers, the webmaster can confirm this to Google. This will start a month long session to check for instances of the issue on the site. If it is no longer present in any URLs on your site during the 28-day window, the issue is considered fixed.

Reducing the Impact on Site Speed from Third-Party Tags

One commonly overlooked part of auditing CWV is third-party tags, which every site hosts. These are snippets of JavaScript code that are generated from third-party servers to display ad creatives or gather/track user engagement activities (i.e. clicks, views, purchases etc.).

Such tags, in many cases, are critical for a website’s functionality and/or to provide key insights into user interaction with the website. However, it all comes at the cost of page load speed. This is because too many calls are made to the server with multiple threads, which slows loading speed and has a negative impact on user experience, particularly on mobile devices and networks. As you can imagine, this will be reflected in a lower Core Web Vitals score.

Therefore, it is important to follow the steps below for auditing and tag optimisation, in order to achieve the best CWV results:

  1. Perform a full tag inventory, including data collected by each tag
  2. Remove unused or duplicate tags
  3. Understand tag loading patterns and check if you can delay loading for some of them

In Summary

By auditing your CWV and also optimising and prioritising the tags that are loaded (potentially using a tag manager to be more strategic with loading times), you increase your chances of finding the right balance between tags used on the site, functionality, and data collection. This will of course result in a faster website, which will provide a more positive user experience and also achieve a good Core Web Vitals score for your pages, all of which are considered important rankings factors for 2021 and beyond.