Important new paper by Alan Gerber, Gregory Huber, and Seth Hill estimates the effects of moving to an all vote-by-mail system in the State of Washington.

The overall estimated impact of the change to VBM is 2.6% in presidential years, 3.3% in midterm years, and 3.8% in odd years, very close to estimates I’ve provided before (see here for an estimate based on national data and here for Oregon estimates).

Using individual level voter files, they find even larger effects on low propensity voters: 9.8 percentage points for those in the file who were only registered to vote at a polling place in 2008, followed by a 3.8 percentage point increase for those who did not vote in 2006, 7, and 8.

The piece is a nice empirical demonstration of how to work with individual voter history files as a way to evaluate an election reform, and it’s also nice to see that the oft-quoted “2-4% effect” (mostly coming out of my mouth) is sustained once again.