Understanding Lighthouse 6.0

Since Google's page speed changes in 2018, publishers have engaged in a mad dash to figure out how to build dynamic sites and maintain performance scores that meet the search engine's user experience expectations. Now in 2020, when people are online more than ever, excellent site performance is no longer optional.

Earlier this year, Google released version 6.0 of Lighthouse. As a reminder, Lighthouse is a tool built into the latest version of Google Chrome that helps you determine how well your site is performing, and tells you which pages on your site need improvement.

Let's look at what's changed. Most importantly, Lighthouse has added two new metrics into its formula for page speed:

• Largest Contentful Paint (LCP): A website's LCP is the time it takes to load the main content on a page.
• Total Blocking Time (TBT): TBT measures a page's load responsiveness to quantify how long a page is non-interactive prior to becoming interactive. You want your site to have a low TBT to maintain its usability.

Here's a look at how these new metrics stack up against the previous version of Lighthouse:

From web.dev.

As you can tell, First Contentful Paint (FCP) has gained a bit more weight in Lighthouse 6.0. FCP measures the time from click to the time when a user's browser renders the first bit of content from the Document Object Model (DOM), which is your site's HTML structure.

By contrast, two metrics dropped considerable weight. The first is Time to Interactive (TTI), which measures the time from when the page starts loading to when its main subresources have loaded and it's capable of reliably responding to user input quickly. You want your site to have a low TTI to maintain its usability. Second is Speed Index (SI), the measurement of how quickly the contents of a page are populated. Both dropped in Lighthouse's speed calculation by 12–18%.

What Lighthouse 6.0 Means for Your Site

These new metrics haven't changed Lighthouse's primary function — to determine if your website loads as quickly as possible. The new insights are just a new way to measure this more accurately. LCP measures load time, and TBT determines how long a page remains inactive for a user, two data points that have the potential to diminish the overall user experience if not optimized correctly.

It's now even more important to focus on how long it takes your page to render for every use. This means JavaScript, third-party applications, and any other dynamic media must be optimized for speed. Any slowdowns will dramatically hurt both your LCB and TBT scores.

Here's another way to visualize these changes:

From web.dev.

Understanding Core Web Vitals

Shortly after the launch of Lighthouse 6.0, Google announced an update to the way it evaluates overall page experience. This change is measured by three metrics called the Core Web Vitals, that can be tracked in the Google Search Console. The Core Web Vitals will play an important role in how Google measures overall page performance, and could be a make-or-break factor for your site's survival.

Google says 2020's Core Web Vitals are the following data points:

Largest Contentful Paint (LCP): A website's LCP is the time it takes to load the main content on a page. Google wants a LCP to happen within 2.5 seconds of when a page first starts loading.

First Input Delay (FID): This metric quantifies a user's experience when trying to interact with unresponsive pages. This usually occurs between FMP and TTI. You want your FID score to be low to prove the usability of your site. According to Google, pages should haven an FID of less than milliseconds.

Cumulative Layout Shift Score (CLS): CLS determines how often your users experience unexpected layout shifts or changes on a page. To ensure visual stability, you want your CLS score to be low. Google wants pages to maintain a CLS score of 0.1.

These three metrics will work alongside Google's other ranking factors, including a site's mobile friendliness and safety features, to determine its overall page experience and visibility on search.

From Google

Google says it will always consider informative, quality content as its number one search signal. However, if two websites both have quality content, but one site has better Core Web Vitals, the site with a better page experience will always outrank any site that isn't optimized for performance.

"By adding page experience to the hundreds of signals that Google considers when ranking search results, we aim to help people more easily access the information and web pages they're looking for, and support site owners in providing an experience users enjoy." - From Google's page experience announcement, May 2020.

Secure Your Site's Future

The RebelMouse platform evolves alongside Google's algorithm, and our team of growth experts spans all time zones to make sure our sites are optimized for page experience with every new article.

To do this correctly, it takes a lot of optimization to perfect every moment of your site's load time. We've mastered Lighthouse 6.0's formula already, and our scores are drastically outperforming every other CMS on the market.

Our jaw-dropping page speeds have empowered us to guarantee a PageSpeed Insights score of 90+ for every site we power. We've done this through a simplified version of code that still allows for ads, videos, and third-party applications to load quickly.

Now that you're well up to speed on how Google's measures site experience, let'ss take a look at some of our performance scores:

Here's how those scores compare to some of the biggest names on the web:

At RebelMouse, performance is a pillar of our company's culture. We've taken Lighthouse scores seriously for years, and have leveraged them to ensure our sites are constantly high performing. It's why we outperform some of the biggest sites on the web. And like with any pillar of a company's culture, optimizing for high performance is never a one-time effort. Our engineers have been crafting and tuning our platform to address these new standards long before they surfaced.

If you want to publish alongside the speed of the web, request a proposal today and let's start working together.