During a discussion with Google’s John Mueller at SMX Munich in March, he told me an interesting bit of data about how Google evaluates site speed nowadays. It has gotten a bit of interest from people when I mentioned it at SearchLove San Diego[1] the week after, so I followed up with John to clarify my understanding.
The short version is that Google is now using performance data aggregated from Chrome users who have opted in as a datapoint in the evaluation of site speed (and as a signal with regards to rankings). This is a positive move (IMHO) as it means we don’t need to treat optimizing site speed for Google as a separate task from optimizing for users.
Previously, it has not been clear how Google evaluates site speed, and it was generally believed to be measured by Googlebot during its visits — a belief enhanced by the presence of speed charts in Search Console. However, the onset of JavaScript-enabled crawling made it less clear what Google is doing — they obviously want the most realistic data possible, but it's a hard problem to solve. Googlebot is not built to replicate how actual visitors experience a site, and so as the task of crawling became more complex, it makes sense that Googlebot may not be the best mechanism for this (if it ever was the mechanism).
In this post, I want to recap the pertinent data around this news quickly and try to understand what this may mean for users.
Google Search Console
Firstly, we should clarify our understand of what the "time spent downloading a page" metric in Google Search Console is telling us. Most of us will recognize graphs like this one:
Until recently, I was unclear about exactly what