On Twitter, Google's Matt Cutts confirmed that Google uses a form of author rank or author specific authority in the in-depth articles ranking formula.
Mark Traphagen questioned Google when Amit Singhal told Danny Sullivan at SMX Tuesday night that author rank is not used in the algorithm. Mark tweeted it and Matt Cutts responded, "to be fair, it does come into play in some ways." Where, in in-depth articles.
Here is Matt's tweet:
@marktraphagen to be fair, it does come into play in some ways. For example, in-depth articles use that data, I'm pretty sure.
— Matt Cutts (@mattcutts) March 12, 2014
To be fair, Google has gone on record about using author authority in the future within their ranking algorithm. It is something they clearly want to use and they are working on it.
But right now, it is used for knowing which articles to show in the in-depth section of the Google results.
Forum discussion at Twitter.