First, I should clarify something: Quality Score, used in relation to Google, is a term used in 2 contexts: one, in Google Ads (where it’s a real metric), and second, in SEO, where it’s a less tightly-defined term that’s not (currently) a metric.
So, one term, but 2 different meanings, depending on the context.
If you’ve been in the content aspect of SEO for a while, you’ve probably heard of Quality Score.
Currently, Quality Score is not displayed publicly, and, as far as we know, it’s not a metric that you can glance at.
During Google’s most recent English SEO Office-Hours (November 12th, 2021), John Mueller addressed a question about Quality Score.
The video below has been queued to the 34-minute, 41-second mark.
The question was:
“When you say 'Improve the quality of your website,' is this quality something that is quantifiable, or is it simply a term used to determine how multiple algorithms look at your website?”
John’s response (which I’ve edited for clarity) was:
“I don't think it's quantifiable in the sense that we have a Quality Score like you might have for Ads when it comes to Web Search.
“And we have lots of different algorithms that try to understand the quality of a website.
“So it's not just one number or anything like that.”
Google’s Concerns About Releasing a Quality Score Metric
“From time to time, I talk with the search quality team to see if there's some quality metric that we could show, for example, in Search Console. But it's super tricky because we could create a separate quality metric to show in Search Console. But then that's not the quality metric that we actually use for search, so it's kind of almost misleading.
“And if we were to show exactly the quality metric that we use, then, on the one hand, that opens things up for abuse, and, on the other hand, it makes it a lot harder for the teams internally to work on improving this metric.
“So that's kind of the tricky balance there.
“At some point, maybe we'll have some measure of quality in Search Console, though.”
So, there you go: in SEO, for Google to release a Quality Score metric would create some obstacles internally, and maybe more importantly, set things up to be easily exploited (abused).