Which page title is Google using for ranking, my original or their autogenerated one?

• After reading in last month's issue of SEN the Titlepocalypse update, I'm wondering which title Google is using for ranking purposes, the original title or the new page title that they generate?

Answer:

As noted in last month's SEN update that you referenced, Google is now generating their own title descriptions in the SERPs for a small percentage (recently reduced from 20% to 13%) of web pages "making use of text that humans can visually see when they arrive at a web page" according to their announcement.

Google search advocate, John Mueller, addressed that question in a recent office hours. Here's what he said: (emphasis added)

You never know how these things evolve over time, but at least at the moment it is the case that we continue to use what you have in your title tag, in your title element, as something that we can use for ranking.

It’s not like something that replaces everything for the website, but it is a factor that we use in there. Even if when we display the title for your page we swap out maybe that one keyword that you care about, we would still use that for ranking.

John goes on to warn that you shouldn't be thinking...