Google Chrome announced a major change in Lighthouse 10, which saw the removal of the Time To Interactive (TI) score. Tests indicate that the majority of web pages will see an improvement in their performance scores, with more than half of the web pages seeing a score improvement of more than 5 points.
Reaction time – TTI
The Interaction Time score measures how long a page takes to become interactive for site visitors. The result is a multi-step calculation that measures resource load to determine when a user can do things like click a button or use site navigation.
The reason for removing Time To Interactive is because the other metrics, Largest Contentful Paint (LCP), Speed Index, and Total Blocking Time together are better measures of web page load time.
Chrome blog post explained:
Largest Contentful Paint (LCP) and the speed index are usually better heuristics for the contents of a page being loaded than the number of active network requests. At the same time, Total Blocking Time (TBT) handles long tasks and main thread availability more aggressively, and although While it’s not a direct proxy, it tends to correlate better with core web fundamentals as measured in the industry.”
Tests on more than 13 million web pages indicate that 90% of web pages will see improved results and 50% of web pages will see performance improvements of more than 5 points.
Time To Interactive’s score weighting has, since Lighthouse 8, gradually decreased. This allowed the other measures to be further weighted so that TTI ultimately contributed less to the final outcomes.
Change has been made to Improved accuracy of page speed UX metrics And to encourage publishers and SEOs to focus on doing things like reducing heavy javascript, something That was getting worse.
The decision to slowly reduce weighting has been explained as developing page speed metrics to become more accurate.
A note in the Lighthouse 8 documentation explained:
“As with all Lighthouse Score updates, changes are made to reflect the latest in how we measure user experience quality comprehensively and accurately, and to focus attention on key priorities.”
The Time To Interactive score will still be available in the Lighthouse JSON output, with the score weighted to zero.
When will Lighthouse 10 changes arrive?
Changes made to the Google Lighthouse are now available on the PageSpeed Insights tool. The Chrome beta, called Canary, also contains the new version of Lighthouse 10.
Lighthouse 10 will be available in Chrome 112, which is currently scheduled for release on March 29, 2022. The latest version of Chrome is 110.
Read about removing TTI from Lighthouse 10:
What’s new in Lighthouse 10 – Changing scores
Featured image by Shutterstock / Roman Sambourskyi
