Google spokesman John Mueller once again confirmed that updates to site quality assessment algorithms, such as Core and Quality updates, can affect not only the positions of sites in search, but also their crawling and indexing by Google robots.
This is because since Google does not consider that most of the site should be shown in search, then it is not worth spending time crawling and indexing this content.
However, incomplete indexing also applies to good sites – it has long been known that not all URLs fall into the Google index, “because there is a lot of other content on the Internet,” says SearchEngines.
Keep in mind that Mueller has repeatedly said that Google does not crawl and index all pages of the site. According to him, this is completely normal, and if 20% of the site’s pages are not indexed, this is not a cause for concern.
He also advises webmasters to keep working on the site and improve its quality. This is necessary so that Google systems can see that it makes sense to crawl and index this resource, notes NIX Solutions. Then, over time, more content will get into the index.