Posted by Mushan Yang and Xiangyu Luo, Software Engineers
PageSpeed
Insights provides information about how well a page adheres to a set of best
practices. In the past, these recommendations were presented without the context
of how fast the page performed in the real world, which made it hard to
understand when it was appropriate to apply these optimizations. Today, we're
announcing that PageSpeed Insights will use data from the Chrome
User Experience Report to make better recommendations for developers and the
optimization score has been tuned to be more aligned with the real-world data.
The PSI report now has several different elements:
The Speed score categorizes a page as being Fast, Average, or Slow. This is
determined by looking at the median value of two metrics: First Contentful Paint
(FCP)
and DOM Content Loaded (DCL).
If both metrics are in the top one-third of their category, the page is
considered fast.
The Optimization score categorizes a page as being Good, Medium, or Low by
estimating its performance headroom. The calculation assumes that a developer
wants to keep the same appearance and functionality of the page.
The Page Load Distributions section presents how this page's FCP and DCL
events are distributed in the data set. These events are categorized as Fast
(top third), Average (middle third), and Slow (bottom third) by comparing to all
events in the Chrome User Experience Report.
The Page Stats section describes the round trips required to load the page's
render-blocking
resources, the total bytes used by the page, and how it compares to the
median number of round trips and bytes used in the dataset. It can indicate if
the page might be faster if the developer modifies the appearance and
functionality of the page.
Optimization Suggestions is a list of best
practices that could be applied to this page. If the page is fast, these
suggestions are hidden by default, as the page is already in the top third of
all pages in the data set.
For more details on these changes, see About PageSpeed
Insights. As always, if you have any questions or feedback, please visit our
forums
and please remember to include the URL that is being evaluated.
