Google’s John Mueller clarified that content may be still moved to mobile-first indexing despite not passing the mobile usability test.
This topic came up during the January 11th Google Webmaster Central hangout.
A site owner submitted a question regarding what they perceived to be conflicting information in Search Console.
Search Console’s ‘mobile usability’ report shows the site has a number of valid URLs.
However, the information does not line up with what Search Console is telling them about pages being ready for mobile-first indexing.
Mueller responded by saying mobile usability is “completely separate” from mobile-first indexing.
Web pages can be moved to mobile-first indexing even if they’re not considered usable on mobile.
Mueller provided an example, saying PDFs can be added to mobile-first indexing even though they are terrible to navigate on mobile.
As long as Google can crawl all the text, and it can be displayed on a mobile device, then it can be added to mobile-first indexing.
So, the key takeaway here is:
Do not look to Google’s mobile usability test, or the report in Search Console, as an indication of whether your site is ready for the mobile-first index.
Hear the full question and answer in the video below, starting at the 41:12 mark.
“So, first off, again mobile usability is completely separate from mobile-first indexing.
A site can or cannot be usable from a mobile point of view, but it can still contain all of the content that we need for mobile-first indexing.
An extreme example, if you take something like a PDF file, then on mobile that would be terrible to navigate. The links will be hard to click, the text will be hard to read.
But all of the text is still there, and we could perfectly index that with mobile-first indexing.
Mobile usability is not the same as mobile-first indexing.