Although the notion of Quality Score seems to have originated within the context of paid advertising, it is a term that I’ve heard used in SEO contexts, as well.
If I were going to define Quality Score (not as defined within paid ads, but as used in SEO talks), I’d say that it’s a measure of the overall content quality of your site.
That is, if a certain portion of your pages is high quality, then your site will have a high quality score.
Within SEO, I don’t think there’s a Quality Score point system like there is in Google Ads; however, because I’ve heard Google’s John Mueller speak about it, it does seem to be a real concept.
With that, comes the notion that if your site has a lot of low-quality pages, those pages can bring the overall Quality Score of your site down.
And that leads us to a question that was asked during the most recently-uploaded recording of a Q&A session released by Google: English Google SEO office-hours from September 17, 2021.
The question, basically, was (and I’m re-wording it), “Considering old news and old content, is it worth removing, no indexing, or disallowing them?”
The person who asked the question also said this was a site that’s over 10 years old, with 3 million pages.
John’s response (which is from an SEO perspective) was that “I don’t think you would get a lot of value out of removing just old news so…it’s also not something I would recommend to news websites, because sometimes, all the information is still useful.”
And, this makes sense. Old pages can still be useful in the future.
Think about someone who, let’s say in 25 years from now, has to do a research project and needs the information that you have.
John goes on to state that, “…so…from that point of view, I wouldn’t do this for SEO reasons.
“If the reasons why you want to remove content or put it into…an archive section on your website for usability reasons or for maintenance or whatever, that’s something that that you can definitely do, but I wouldn’t just blindly remove old content because it’s old.”
That said, it’s believed that there can be a net quality score increase if you remove low-quality content, whether it be old or new.
So, in short, there’s no need to remove old content (at least, from an SEO perspective). That’s different from removing low-quality content.