Google has updated its PageSpeed Insights report to include data from the Chrome User Experience Report. Previously, PageSpeed Insights information was provided without the context needed to apply the information presented and correct any speed issues. By using the Chrome User Experience report for data, Google expects to be able to provide more useful information to developers and make the optimization score more aligned with real-world data.
The improved PageSpeed has 5 different elements.
The Speed Score
The Speed score categorizes a page into one of three categories: Fast, Average, or Slow. A page’s median value of First Contentful Paint (FCP) and DOMContentLoaded (DCL) is used to determine the speed. For both metrics, a page is “Fast” if the median value of the metric is in the fastest third of page loads. Conversely, a page is “Slow” if the median value of the metric is in the lower third. The middle third is considered “Average.”
The Optimization Score
The Optimization Score checks how well a page is following Google’s list of common performance best practices, using a grading scale that goes from 0 -100. When determining PageSpeed Insights Optimization Score, Google measures time to above-the-fold load, which is how long it takes a browser to render the first visible portion of a page, and time to full page load, which is how long it takes for a webpage to be fully rendered.
In order to be classified as “Good,” a page must score 80 or above. To score an 80 or above, a page must apply most performance best practices. “Medium” pages score between 60 and 79, which means they are missing some common optimizations and there is so room for further optimization. Anything lower than 60 will get a page marked as “Low,” which means the page is not optimized and could use significant improvement.
Page Load Distributions
This is where the Chrome User Experience could potentially make a big difference. By comparing a page’s performance to that of other pages, Google will be able to determine an overall page Speed score. To be given a “Fast” rating, every metric must be fast based on what the Speed score returns. If any part of the page is slow, the page will be placed in the overall “Slow” category. An overall “Average” rating is reserved for all other cases.
The Page Stats section tells a page owner about a page’s render-blocking resources and total bytes used. It will also compare the median number of round trips and bytes used in the data set. This information can tell a developer if they should modify the appearance and functionality to make the page load faster.
Optimization Suggestions tell a page owner which best practices could be applied to the page. This won’t be displayed if a page is already in the top third of all pages.