Google's John Mueller in a video conference talked about why parts of the site go up or down after an algorithm update

On Twitter, Glenn Gabe posed a question to Mueller that during a major update rollout, website quality is calculated based on overall site signals, and then that site quality score is progressively propagated to each page.

He asked if this could cause some pages to crash and some to increase, while the overall domain traffic would remain the same.


So in a videoconference with experts, John Mueller explained why parts of a website go up or down.

He said that the reason for this may be that some of Google's algorithms are not only trying to look at "the big picture of the website" but also "at the less important parts of the website."

Mueller's answer was as follows:

“It depends on the particular algorithm, what estimates the algorithm can generate at the granular level and what it should guess or guess for other pages that don't have enough data to generate at that granular level. It's ... as if we're trying to understand the relevance of a website. On the one hand, we are trying to look at the big picture of the website. But we're also looking at the less important parts of the website. So, of course, it can happen that something goes up and something falls. And on average across the domain, you will see some changes. Also, there are always many different points that come up with regards to search, and some of them are a little more focused on the domain or the broader picture of the website. And some algorithms focus more on minor parts of the site. "
He also added that even outside of the main update, you can see these shifts throughout the site: some parts will grow, and some will not.

A more complete video can be viewed here: