What is Google PageSpeed Insights?
Google PageSpeed Insights is a free performance analysis tool that evaluates how quickly and efficiently a website loads for users. It provides recommendations for improving loading speed, responsiveness, and visual stability across both mobile and desktop devices.
The tool combines lab data (simulated testing) and field data (real user performance) to highlight technical issues that may affect user experience and search visibility.
A key part of PageSpeed Insights reporting is Core Web Vitals, a set of performance metrics introduced by Google to measure how real users experience a website.
At Great Ape Digital, we use PageSpeed Insights not just to diagnose technical issues, but to identify opportunities to improve engagement and conversion performance.
Why Core Web Vitals Matter for SEO
Core Web Vitals are a major component of Google’s Page Experience signals, meaning they play a role in how websites are evaluated for search rankings.
However, their importance goes far beyond SEO. These metrics measure how a website actually feels to use.
A fast, responsive website builds trust immediately. Visitors are more likely to stay on the page, interact with content, and complete actions such as purchases or enquiries.
In simple terms, improving Core Web Vitals often leads to:
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Lower bounce rates
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Higher engagement
- Better conversion rates
- Stronger search visibility
The Three Core Web Vitals Explained
Google currently measures three primary metrics that define Core Web Vitals.
Largest Contentful Paint (LCP)
Largest Contentful Paint (LCP) measures how quickly the main content of a page becomes visible. This is usually the largest element in the viewport, such as a hero image, video, or headline.
LCP represents how quickly users feel the page has loaded.
How to Improve LCP
Common causes of slow LCP include large images, render-blocking code, or slow server response times.
Ways to improve LCP include:
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Compressing and optimising images
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Reducing unused CSS and JavaScript
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Improving server performance
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Using caching and a CDN
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Preloading key resources
Improving LCP ensures visitors can access meaningful content quickly.
Interaction to Next Paint (INP)
Interaction to Next Paint (INP) measures how quickly a page responds when a user interacts with it.
For example:
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Clicking a button
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Opening a menu
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Submitting a form
If the browser is busy processing heavy JavaScript, users may experience delays.
How to Improve INP
To improve responsiveness:
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Reduce unnecessary JavaScript
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Break large tasks into smaller processes
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Defer non-critical scripts
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Optimise event handling
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Limit third-party scripts
A strong INP score ensures the site feels smooth and responsive during interaction.
Cumulative Layout Shift (CLS)
Cumulative Layout Shift (CLS) measures how stable a page layout remains during loading.
Unexpected movement, such as text shifting or buttons moving, can create frustration and lead to accidental clicks.
How to Reduce CLS
Common improvements include:
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Setting width and height for images and videos
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Reserving space for ads or embeds
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Optimising font loading
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Avoiding dynamic content shifts above existing elements
A stable layout creates a more professional and trustworthy user experience.
Why Core Web Vitals Don’t Always Appear in PageSpeed Insights
When testing a page in Google PageSpeed Insights, you may sometimes see the message “Core Web Vitals assessment: Not applicable” or notice that the field data section is missing.
This usually happens because Google does not yet have enough real-world user data for that page.
Core Web Vitals in PageSpeed Insights are based on the Chrome User Experience Report (CrUX), which collects performance data from real Chrome users. If a page receives limited traffic, there may not be enough data for Google to generate reliable metrics.
Common reasons include:
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Low traffic pages – A minimum number of user visits is required before data can be reported.
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New or recently updated pages – CrUX metrics are based on recent usage data, so they may take time to appear.
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URL variations – Testing URLs with parameters or non-canonical versions may not match the version Google tracks.
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Indexability issues – Pages blocked from indexing or returning errors may not be included in CrUX data.
If Core Web Vitals are unavailable, the Lighthouse lab data within PageSpeed Insights can still be used to identify performance improvements while real-world data accumulates.
Tools to Measure Core Web Vitals and PageSpeed
Several tools help monitor and improve website performance.
Google PageSpeed Insights provides quick diagnostics and recommendations. Google Lighthouse offers deeper technical analysis, while Google Search Console shows aggregated Core Web Vitals data across groups of pages.
Using these tools together gives a clearer picture of how users experience your website and where improvements are needed.
Ongoing Monitoring and Performance Optimisation
Improving PageSpeed and Core Web Vitals is not a one-time task. Website performance can change as new features, scripts, or content are added.
Regular optimisation activities include:
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Compressing and optimising media
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Reducing unnecessary scripts
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Improving caching strategies
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Monitoring third-party tools
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Conducting regular performance audits
Consistent monitoring ensures websites remain fast, responsive, and stable over time.
Conclusion
Google PageSpeed Insights helps businesses understand how their website performs for real users. By analysing Core Web Vitals and other performance metrics, it highlights opportunities to improve loading speed, responsiveness, and visual stability.
Websites that prioritise performance deliver better user experiences, build trust faster, and support stronger engagement and conversions.
Optimising for PageSpeed Insights ultimately helps create websites that perform well for both users and search engines.
Learn more about Technical SEO here.
