If you move from one state to the next, you may find dramatic differences in election administration. Back in my home state of California, I registered as a permanent absentee voter. Prior to each election, I received my ballot in the mail, which I completed at my leisure and returned by mail. Here in Utah, I vote in person on those creepy Diebold machines after waiting in line for too long.

In a recent article, Larocca and Klemanski look to see whether these state-to-state variations affect turnout. They conclude that these variations do matter. They find that permanent no-excuse absentee voting, nonpermanent no-excuse absentee voting, and Election Day registration all have positive correlations with turnout. They find that universal mail voting (where everybody is an absentee voter) and voter identification requirements have marginal positive correlations.

I use the word “correlation” intentionally in the previous paragraph. Larocca and Klemanski speak as though these are causal relationships: If a state adopts one of these laws, its turnout will rise. But it’s not clear to me that they’ve really shown causality.