Interesting looking working paper here. Can't access it and I'm not going to bother signing in right now. He talks about credits instituted during the Great Recession so I'm guessing he's not looking at Georgia (although I believe they expanded it).
I noticed the opportunity for an RDD application years ago but never got to write it up until last fall. I'd spend time submitting it somewhere now except I've got this mountain of end-of-semester work.