What is Google’s PageSpeed Insights tool?Google’s “PageSpeed Insights” tool (GPSI for short) “indicates how well a page performs on the Chrome UX Report and suggests performance optimizations.” In other words, they evaluate whether your site is following today’s standards and best practices.
How is “site speed” measured by this tool?Google scores your site using two different metrics:
- Speed (new, don’t worry about this one yet)
- Optimization (start here)
Speed scores are measured values and difficult to understand in their current formThe “speed” metric is a 30-day average of actual load times from Chrome users and updates weekly. The FCP timing is essentially how long it takes for your site to “look” ready (even if it’s still loading), while DCL is how long it takes to receive & read the first set of code sent from your server (website) to the browser (reader). This is different from other tools, which tend to measure “speed” as your “load time.”
- That can be problematic since load time cannot be blindly mapped to user experience. A reader may be able to access and interact with your site even as content continues loading and this is generally considered a good thing. When this is the case, a tool measuring your load time will tell you that your site is performing dismally thought the reality is that your readers are very happy – not cool, right?
- Ads are actually a big part of the huge numbers you’re seeing, too. Turn those off, and your load time drops from, say, 33 seconds to 5 – what the what? Well, those tools are measuring how long it takes your site to finish loading, but may have difficulty understanding how your ads load, leading to inflated measurements.
Optimization scores show actionable recommendations for immediate resultsThat brings us to the “optimization” metric, which was previously the only metric GPSI measured, before their January 2018 update to the tool. This is a score calculated by your adherence to the 10 recommendations they provide, and is more lenient today than it was in 2017 or earlier. At Once Coupled, we build our speed audits with information from GPSI’s optimization recommendations, which provide (nearly) ad-independent scores that can measure real-time impact. We’ve discussed these recommendations in length in our previous “Getting to Green” article, but we’ll be touching on some of the big items more during the coming month, so make sure to sign up for blog updates.
Should I focus on speed or optimization?Speed is a difficult metric to measure for a couple reasons:
- It can be more dependent on your server resources and configuration, making it less accessible to the average user (other than simply moving servers or hosts).
- It’s only updated updated every 7 days (and then contains at least 3 weeks of un-optimized data), making it incredibly difficult to track the impact of the improvements you make.