Are pages that are found in the Google Search Console coverage report, under "excluded" and labeled as "Crawled - currently not indexed" a sign that there are quality issues with not just those pages but also the site? Maybe. John Mueller of Google responded to Ori Zilbershtein implying that this may be such a sign.
Ori asked "In GSC there are pages which are "crawled - currently not indexed", in some cases these are extremely important pages in a site, how can a site owner make sure they get indexed?"
John Mueller responded "you can't force pages to be indexed -- it's normal that we don't index all pages on all websites. It's not an issue with "that page", it's more site-wide. Creating a good site structure and making sure the site is of the highest quality possible is essentially the direction."
So here John is saying that this can be more of a site-wide issue and not a specific issue with "that page." He added "Creating a good site structure and making sure the site is of the highest quality possible is essentially the direction," right after that.
Here are those tweets:
You can't force pages to be indexed -- it's normal that we don't index all pages on all websites. It's not an issue with "that page", it's more site-wide. Creating a good site structure and making sure the site is of the highest quality possible is essentially the direction.
— 🍌 John 🍌 (@JohnMu) June 28, 2021
Google defines crawled - not indexed as "Crawled - currently not indexed: The page was crawled by Google, but not indexed. It may or may not be indexed in the future; no need to resubmit this URL for crawling."
We know Google has said numerous times that indexing issues can be related to quality issues with the overall site. For pages to be indexed they need to pass quality checks. And if you see your site being deindexed, that can be a sign of a quality issue.
So it may make sense to try to reduce the "Crawled - Currently Not Indexed" pages as much as possible?
Forum discussion at Twitter.
The discussion has gone on after I posted this:
If there are overall issues with your site, you need to look at the rest of your site, not the URLs that didn't end up getting indexed.
— 🍌 John 🍌 (@JohnMu) July 1, 2021
A lot of things go into whether or not a URL is indexed. I wouldn't ... over-index ... on quality, and I wouldn't assume that overall website quality improvements are simple technical tweaks. Also, significantly improving the quality of a website has effects across the board.
— 🍌 John 🍌 (@JohnMu) July 1, 2021
It's not meant to highlight low quality content issues. See it the same as looking at the performance report and noticing that you're only ranking for a portion of the queries you care about, and only ranking on page 2. It's up to you to decide what to do with that.
— 🍌 John 🍌 (@JohnMu) July 1, 2021