Google's John Mueller said in a video hangout last week at the 37:02 mark that you can see parts or portions of your web site go up or down after an algorithm update. The reason for that is that some of Google's algorithms not only try to look at the "bigger picture of the website" but also "look at smaller parts of a website," he said.
The question John was asked was pretty direct, it was "During the core update rollout, is it like the quality of the website is calculated from the overall site signals, and then this site quality score is propagated to every page gradually, page by page? Is it possible that some pages drop and some pages surge, and the overall traffic to the domain remains the same?"
The answer is, it depends of course. It depends on the specific algorithm, what scores the algorithm can generate at a granular level and what it has to assume or guess for the other pages it does not have enough data to generate at that granular level.
John said "It's-- like, when we try to understand the relevance of a website, on the one hand, we try to look at the bigger picture of the website." He added "But we do also look at smaller parts of a website. So it can certainly happen that some things go up, some things go down. And on average, across a domain, you will see some change, or maybe it'll even out even in kind of weird coincidental cases. So that's certainly possible, the way that you're seeing things there."
"And it's also that there are always a lot of different things that come out with regards to search, and some are a little bit more focused on the domain or on a bigger picture of the website. Some are focused more on smaller parts of a website," John explained.
Which is why he said "so even outside of a core update, you might see these shifts across some parts of your site, and other parts going up, some parts going down."
Glenn Gabe summed it up nicely also in these two tweets:
And regarding Google looking at more granular parts of a site, that's why you can see ups and downs in certain areas of your site during core updates. So, some things are focused on evaluating the site overall & other things are focused on more granular aspects. https://t.co/FqgSoAXv6N
— Glenn Gabe (@glenngabe) December 22, 2020
Here is the video embed to watch it yourself, it is not long, if you click play it will start at 37:02:
Forum discussion at Twitter.
