Why You Can’t Rely Solely on Google PageSpeed Insights for Website Performance and Usability

Google PageSpeed Insights (PSI) is a popular tool for analyzing website performance, focusing on technical aspects like page load speed and web best practices. However, PSI alone doesn’t provide a complete view of your website’s performance and usability.

While helpful, PSI has limitations. It doesn’t measure the full user experience, such as navigation ease, content clarity, or design effectiveness—factors critical for user satisfaction. PSI scores can also be affected by external factors like network conditions or user devices, so a low score doesn’t always mean poor performance for everyone.

For a full picture, combine PSI insights with other tools. Real user monitoring (RUM) shows how real visitors experience your site, user testing identifies usability issues, and A/B testing evaluates how design and content changes impact engagement and conversions.

Blending PSI data with other insights helps you better understand your website’s performance and make informed improvements. Remember, performance isn’t just about speed—it’s about creating a positive, engaging experience for your users.

1. Lab Environment vs. Real User Conditions

PageSpeed Insights operates in a controlled, simulated lab environment to measure performance. While this can offer a consistent baseline, it fails to reflect real-world user conditions. Factors such as different network speeds, device capabilities, geographic locations, and browser variations are completely ignored in this system. For instance, a user accessing your site from a mobile phone on a 3G network may have a vastly different experience compared to the lab environment PSI uses for its analysis.

What’s missing? Real User Metrics (RUM) that show how real users interact with your website under actual conditions.

2. Limited Scope

PSI primarily focuses on front-end performance, such as optimizing images, minifying CSS and JavaScript, and reducing third-party scripts. While critical, these metrics don’t address back-end aspects like:

• Server response times 
• Database query speeds 
• Application performance   

All of these also play a crucial role in a website’s overall speed and usability.

If your site has great front-end optimization but sluggish server performance or a poorly optimized database, your users might still experience delays, something PSI won’t adequately highlight.

3. Narrow Metrics and Scores

PageSpeed Insights relies heavily on specific metrics like Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). While these are important, they don’t paint the full picture of user experience. For instance:

• Does your website have engaging content? 
• Are customers navigating easily to find what they need? 
• Is the checkout or lead conversion process smooth? 

A PSI score doesn’t provide detailed answers to questions like these. Instead, it merely assigns a numerical score, which can sometimes feel arbitrary and disconnected from your business goals.

4. Dependency on Google’s Standards

PSI follows Google’s best practices for optimization, which may not align with every website’s specific needs or strategy. For example:

• A website focused on high-quality visuals (like e-commerce stores) may score poorly due to large image sizes—despite delivering a fantastic user experience for its audience. 
• Custom or niche websites require unique solutions, which might not conform to Google’s rigid criteria but still meet the business’s objectives.

5. Not Designed for Usability Insights

While PSI focuses on technical performance metrics, usability extends far beyond speed. Elements like intuitive navigation, content readability, visual hierarchy, and accessibility are critical usability factors that PSI does not address. For instance, a website may score well in PSI yet have poor usability due to cluttered layouts or confusing calls-to-action (CTAs).

Alternative Tools for Comprehensive Website Performance and Usability Analysis

To measure website performance and usability effectively, it’s important to adopt a more holistic approach with tools and methods that cover real-world metrics, back-end analysis, and user experience:

• Content Delivery Network (CDN) – CDNs are a network of servers strategically distributed across various geographical locations. By caching and delivering content from servers closest to the end user, CDNs significantly improve load times and reduce bandwidth costs. They are essential for maintaining a fast, efficient, and reliable website experience, especially for users spread across different regions.
• Cloudflare – A popular web infrastructure and security platform, Cloudflare offers services such as content delivery network (CDN) integration, DDoS protection, and SSL encryption. It helps enhance the performance and security of websites by reducing latency and ensuring rapid content delivery across a global network of data centers.
• Google Analytics – A powerful tool that tracks and analyzes user journeys, bounce rates, and conversion metrics, providing detailed insights into how users interact with your website. It helps identify areas for improvement and optimize the overall usability to enhance user experience.
• Shopify Web Performance Reports – Tools specifically created for Shopify websites. These tools give detailed, actionable recommendations to improve site speed and overall performance, which will boost customer satisfaction and drive higher conversions for your online store.
• WordPress Tools – Boost your website’s speed and efficiency with plugins like WP Rocket, Query Monitor, and Autoptimize. WP Rocket simplifies caching and performance optimization, Query Monitor helps identify and debug performance issues, and Autoptimize streamlines your site by optimizing scripts, styles, and images. These tools are essential for ensuring a smooth and fast user experience on your WordPress site.
• Website Hosting Performance Tools – Many hosting providers, such as SiteGround or Kinsta, offer built-in tools designed to evaluate and monitor server performance. These tools can help you identify potential issues, optimize your website’s speed, and ensure reliable uptime, all of which are crucial for delivering a seamless user experience.
• Real User Monitoring (RUM) – A dynamic tool that tracks real-time user behavior and performance directly on your website. By analyzing how actual users experience your site, RUM helps you address real-world performance issues and improve overall user satisfaction.
• GTmetrix – A powerful tool that combines detailed performance insights with waterfall charts to identify inefficiencies in both front-end and back-end operations. It provides actionable recommendations to help optimize your website for speed and performance. 
• WebPageTest – A robust platform that offers granular testing features, including real-world user simulation, advanced waterfall analysis, and detailed performance metrics. It is particularly useful for pinpointing specific bottlenecks affecting load times. 

Final Thoughts

Google PageSpeed Insights provides a starting point for understanding a website’s front-end performance, but it should never be the sole tool you use to measure website performance and usability. To make informed decisions, combine it with other tools like GTmetrix or RUM and analyze the real-world user experience across different scenarios.

For website owners, marketers, and developers, focusing only on PSI could lead to missed opportunities to improve crucial aspects of your site. Instead, go beyond the score—understand your audience and their needs to deliver a truly stellar user experience.