What Are Core Web Vitals?
Core Web Vitals are three user-experience metrics that Google uses to evaluate website performance and search engine ranking. Introduced in 2020 and made a ranking factor in 2021, they measure how quickly a page loads, how responsive it is to user interaction, and how stable its visual elements remain during loading.
The Three Metrics
Largest Contentful Paint (LCP) measures loading performance. It tracks when the largest content element on a page becomes visible. Google considers 2.5 seconds good, 2.5-4 seconds needs improvement, and over 4 seconds is poor.
First Input Delay (FID) measures interactivity. It's the time between a user's first interaction (clicking a link, tapping a button) and the browser's response. Aim for under 100 milliseconds. Note: Google is replacing FID with Interaction to Next Paint (INP) in 2024.
Cumulative Layout Shift (CLS) measures visual stability. It quantifies how much page elements shift unexpectedly while loading. A score below 0.1 is good; above 0.25 is poor.
Why It Matters for Media Agencies
For UK marketing professionals, Core Web Vitals directly affect campaign performance. Slow-loading landing pages frustrate users, increase bounce rates, and reduce conversion rates. Poor Core Web Vitals can lower organic search visibility, making paid campaigns more expensive to maintain comparable traffic levels.
If your clients' websites have weak Core Web Vitals scores, they'll rank lower in Google Search results, particularly on mobile devices. This affects organic reach and forces greater reliance on paid channels.
When You'll Use It
Use Core Web Vitals when: - Auditing website performance for clients - Planning media campaigns targeting organic and paid search - Optimising landing pages for paid ads - Benchmarking competitor websites - Justifying website optimisation investment to clients
How to Measure
Google provides free tools: Google PageSpeed Insights, Google Search Console (Core Web Vitals report), and Chrome User Experience Report. These show real-world data from actual site visitors.
Practical Takeaway
Don't ignore Core Web Vitals when planning campaigns. A brilliant creative campaign performs poorly on a slow website. Always include technical performance assessment in your media strategy.