Metrics for Understanding Page Speed Insights

Page Speed has always been an essential factor in how a website performs in search engines and how customers perceive a website to be usable. It can also influence whether or not a user converts or makes a purchase on a website.

We’ve all been guilty at some point of leaving a particularly slow webpage and restarting our search…

Insights into Page Speed

Before we can effectively and sustainably optimize a website for Page Speed, we must first understand what Google (and other search engines) consider when calculating your website’s score on the Page Speed Insights report. While it is clear what aspects are measured and reported, it is not always clear what those metrics are and what they measure.

That is why we have created this guide: to help you understand the Page Speed Insight metrics to make your website more user-friendly and accessible to the end-user.

The Most Contented Paint (LCP)

The Largest Contentful Paint metric is a key metric in the Page Speed Insights report and will play a role in the May 2021 Google Algorithm Update, which we recommend you read up on if you haven’t already. Put, the most contentful The amount of render time spent populating and visualizing the largest image or text block within the viewport specified in your browser is measured by Paint. All LCP is relative to the time the page first began loading.

The Very First Contentful Paint (FCP)

In general, First Paint refers to the precise second that ANYTHING on your browser is rendered. The First Paint is typically a header/banner image at the top of the page you are attempting to load, or it may simply be the background color of the page in question. ‘Painting’ a banner image or page background first creates the illusion of a fast-loading page.

However, there is an additional level to First Paint… First and foremost, Contentful Paint. First, Contentful Paint (FCP) is far more effective at controlling your page speed. It measures how long it takes for the first piece of actual content (whether text/copy or visual assets) to appear on your browser.

To put it simply, FCP is the point at which content that your user can interact with or benefit from becomes visible.

Time to Interactive (TTI)

Time to Interactive (TTI) is another Page Speed metric that is extremely important to Search Engines and (if not more so) to the user. Time to Interactive denotes (as expected) the amount of time it takes for a web page to become fully interactive.

When it comes to SEO and Page Speed, the term ‘interactive’ can be quite subjective; however, Google defines Time To Internative (TTI) using three criteria:

  • The website rendered and displayed helpful information.
  • Most/all visible page elements have had event handlers successfully registered.
  • The page now responds to user interactions quickly and effectively, usually within 50milliseconds.

Simply put, Time To Interactive is the point at which your site/web page visitors can view, navigate, and engage without encountering any problems or delays.

Index of Rapidity

Speed Index is a simple concept (this is an anomaly in the world of SEO, where everything is usually mind-blowingly complex). As defined by Google, a site’s Speed Index measures the time (in seconds) it takes for the content on your web page/site to become visually populated.

Google benchmarks a web page’s Speed Index score (obtained using the Speedline Node.js module) against the HTTP Archive data when calculating the index.

Time Spent on Blocking

With this metric, you can see how long (seconds) it takes for a web page to respond to user input. User inputs like mouse clicks, keyboard presses, and screen taps are examples of this.

It is possible to calculate Total Blocking Time by adding all ‘Long Tasks’ between the FCP and the TTI points. After that, any task that takes more than 50 milliseconds is considered “Long Task,” and the Total Blocking Time (TBT) is calculated; thus, a task taking 70 milliseconds would result in a TBT of 20 milliseconds, for example.

Layout Modifications Added Together (CLS)

In May 2021, CLS will once again play a significant role in the CWV Algorithm Update (and again, we encourage you to learn more about this via our guide). A layout shift occurs every time a visible element moves or shifts suddenly from one frame to another.

Have you ever gone to click something on a webpage, and just before you do… the whole page (or at least most of it) moves suddenly… and you end up clicking the wrong thing? We’ve all been there… and it’s called Cumulative Layout Shift.

Put: Cumulative Layout Shift is the sum of all unexpected and sudden layout shifts that occur during a web page’s lifespan during a user’s sessions.

Finally, do you require assistance in enhancing your Page Speed results? Struggling to make your site more user-friendly? Our teams of experts would be happy to help!