Google's John Mueller said in a video hangout on Friday that changing your structured data format from microdata to JSON-LD would not lead to many of your pages being removed from the Google index. He said this in response to a complaint about this.
John said this at the 52:39 mark into this past Friday's hangout. He said changing "from microdata to JSON-LD would not result in pages being dropped from the index."
The webmaster recently updated his 150 million pages of structured data from using microdata to JSON-LD and noticed 98% of the structured data on Google disappeared and a loss of over 40 million pages indexed in Google. John believes this is a result of some sort of technical issue since Google would not remove indexed pages over a structure data change.
Here is the video embed:
Here is the transcript:
Structure data question.A website with over 150 million pages updated structured data from microdata to JSON-LD three months ago. We used Google tools to test and optimize everything is exactly as Google suggests however we lost 98% of the structured data on Google and a loss of over 40 million pages from the index. What's up with that?
So if you're losing pages from indexing that wouldn't be related to how you use structured data. That sounds like something completely separate.
It does kind of worry me if you're losing a lot pages from indexing that maybe there's some technical reason behind that with regards to also how we can pick up a structured data. Because if we can't index those pages we can't use a structure that are there.
So I would as a first step trying to figure out why what is happening with those 40 million pages. Are they really critical pages for your site. What what happened with them? Like check out in the new Search Console, you can use the inspect URL tool to see does Google know about these pages, did Google decide just not to index them? Was maybea technical issue why we couldn't index them?
All of that should be fairly solvable in the new Search Console.
Obviously with 40 million pages you have to find some representative sample pages, you can't test them all. But that's what what I would mostly aim for.
But definitely the change from microdata to JSON-LD would not result in pages being dropped from the index.
Forum discussion at YouTube.
Note: This story was pre-written and scheduled to be posted now, I am currently offline for a holiday.