Was Vance Joseph a good defensive back coach?

Through three games this season our once-vaunted secondary has fallen far. We are currently 25th in the league in completion % allowed, 18th in TD% (% of throws that result in a TD), tied for 14th in interception % (% of throws that we intercept) and 23rd in QB Rating allowed (we are allowing a QB rating of 102.2).

While I know that Vance Joseph is not the defensive coordinator or the defensive backs coach, the question was raised in the snap count post as to whether or not Vance Joseph was a good DB coach in the NFL. So I went looking for data to determine an answer to this question. I looked at league rank in completion % allowed, passing TDs allowed, passes intercepted and QB rating allowed for all of the defensive backfields that he coached (directly or indirectly) during his time as an NFL assistant. Below is the data - with league rank in the four right-hand columns.

So his defensive backfield stunk while he was the DB coach in San Francisco. He had an elite unit for his first two seasons in Houston that faded badly in 2013. He defensive backfield in Cincy was one of the best units in the league for his two seasons there. When he ascended to the defensive coordinator role with the Dolphins for the 2016 season, his defensive backfield was average.

My conclusion from looking at the data is that Vance Joseph can be a very effective DB coach. If we were to apply this same method to Joe Woods, I’m guessing that we wood get a similar result set (but I did not pull those numbers together) - I might be talked into doing that in the comments section though.

All data is from www.NFL.com and/or www.pro-football-reference.com.