From Developer to User-Centric Metrics: A Shift in Web Performance Optimisation

The problem with developer metrics: #

Developer metrics have long been the go-to for measuring website performance. While these metrics provide valuable insight into the technical aspects of a website's performance, they don't always align with user experience. For example, a website may load quickly according to developer metrics, but still feel slow and unresponsive to users. By focusing solely on developer metrics, we can end up optimising for technical metrics at the expense of user experience.

The importance of user-centric metrics: #

User-centric metrics are crucial for understanding how users experience a website. They include factors like time to interactive, page load speed, and others. One important aspect of user-centric metrics is perceived performance, which refers to how quickly a website appears to load from the user's perspective. Perceived performance is influenced by a variety of factors, such as the visual design of the website, the order in which page elements are loaded, and the responsiveness of user interactions. By focusing on user-centric metrics, we can gain insight into the perceived performance of a website, and optimise it to deliver a better user experience. For example, a site with 100 requests that is usable within 1.5 seconds is vastly superior to a site that has 32 requests and isn't usable for 7 seconds. Despite having fewer requests, the second site may be slower overall and result in a poorer user experience. By prioritising perceived performance, we can ensure that a website feels fast and responsive to users, even if it may not technically be the fastest website around. By improving perceived performance, we can also reduce user frustration and improve overall engagement with the website.

Balance between developer and user-centric metrics: #

While user-centric metrics are crucial for web performance optimisation, it's important to strike a balance between developer and user-centric metrics. By using both sets of metrics, we can gain a comprehensive understanding of website performance. By optimising for both developer and user-centric metrics, we can ensure that a website not only performs well technically, but also delivers a great user experience.

Important metrics to measure page experience: #

When it comes to measuring website performance, there are a variety of metrics that can be used to assess different aspects of performance. Some of the most commonly used metrics include:

• First Contentful Paint (FCP): measures the time it takes for any part of the page's content to be rendered on the screen after the page starts loading.
• Largest Contentful Paint (LCP): measures the time it takes for the largest text block or image element to be rendered on the screen after the page starts loading.
• First Input Delay (FID): measures the time it takes for the browser to respond to a user's first interaction with the site, such as clicking a link or tapping a button.
• Interaction to Next Paint (INP): measures the latency of every tap, click, or keyboard interaction made with the page, and selects the worst interaction latency of the page to describe its overall responsiveness.
• Time to Interactive (TTI): measures the time it takes for the page to become visually rendered, for its initial scripts to load, and for it to be capable of reliably responding to user input quickly.
• Total Blocking Time (TBT): measures the total amount of time between FCP and TTI where the main thread was blocked for long enough to prevent input responsiveness.
• Cumulative Layout Shift (CLS): measures the cumulative score of all unexpected layout shifts that occur between when the page starts loading and when its lifecycle state changes to hidden.
• Time to First Byte (TTFB): measures the time it takes for the network to respond to a user request with the first byte of a resource.

Some of these metrics are measured in a lab environment, where a controlled test is performed, while others are measured in the field, where real-world user interactions are analysed. By understanding the different metrics available and how they relate to user experience, website owners and developers can take steps to optimise their sites and improve the overall user experience.

Tools for measuring user-centric metrics: #

There are several tools available for measuring user-centric metrics, including Lighthouse, WebPageTest, and others. These tools can help you gain insight into how users are experiencing your website. By using these tools to measure user-centric metrics, you can identify areas for improvement and optimise your website for the factors that matter most to users.

Google's Core Web Vitals assessment: #

You might already have heard of something called Core Web Vitals. They're a set of user-centric metrics introduced by Google as part of their Page Experience Ranking factor. These metrics measure how users interact with your site, and by optimising them, you can give your users a better experience.

Basically, Core Web Vitals focus on three things: how fast your site loads, how easy it is for users to interact with it, and how stable it is visually. By making sure your site meets these metrics, you can keep your users happy and engaged. And that's what we all want, right?

So, if you want to improve your website's performance and make your users happy, start paying attention to Core Web Vitals.

Conclusion: #

In conclusion, it's becoming increasingly important to shift the focus from developer metrics to user metrics when it comes to web performance optimisation. By prioritising user metrics, we can gain a better understanding of how users experience a website and optimise for the factors that matter most to them. By striking a balance between developer and user metrics, we can ensure that a website not only performs well technically but also delivers a great user experience. As the internet continues to evolve, it's crucial that we adapt our approach to web performance optimisation to meet the changing needs of users.

Happy speeding!