If you've previously looked at RI's math scores, particularly compared to other New England states, it is pretty clear that we've been chronically underperforming for some reason (less so in ELA). I don't know why. As far as I know, the main action on the math front in recent years has been switching to the NECAP and associated Grade Level Expectations, and then getting serious about implementation, including working with the Dana Center on that. Regardless, there was clearly room to improve.
Lo and behold, we got a nice bump in both 4th and 8th grade math on the new NAEP. Not so much in Reading. Since essentially none of Gist's RttT agenda has been implemented (no substantial charter expansion in grade 4 & 8, teacher evaluation changes, etc), and the gains were specifically in math, it is reasonable to conclude that plain old improvements in curriculum and instruction should get most of the credit (and maybe demographic changes, I've not looked that deeply). In particular, one of Gist's top priorities is undoing what seems to have worked -- NECAP.