Automatic voter registration impact on state voter registration

Sean McElwee points us to this study by Kevin Morris and Peter Dunphy, who write:

Automatic voter registration or AVR . . . features two seemingly small but transformative changes to how people register to vote:

1. Citizens who interact with government agencies like the Department of Motor Vehicles are registered to vote, unless they decline. In other words, a person is registered unless they opt out, instead of being required to opt in.

2. The information citizens provide as part of their application for government services is electronically transmitted to elections officials, who verify their eligibility to vote. This process is seamless and secure.

In the past five years, 15 states and the District of Columbia have adopted AVR. (Three states — Connecticut, Utah, and New Mexico — have adopted something very close to automatic registration.)

Morris and Dunphy perform some statistical analysis on state-level registration data and report:

– AVR markedly increases the number of voters being registered — increases in the number of registrants ranging from 9 to 94 percent.

– These registration increases are found in big and small states, as well as states with different partisan makeups.

I’m not sure what to think. On one hand, I’d expect this sort of treatment to work; on the other hand, some of the data look weird, such as Oregon in 2015, which suggests that other things are going on besides the treatment:

Lots more registrations in the control group than the non-control group in that year, even though it says that 2015 is before the treatment period. So it seems that there are systematic differences between treatment and control groups. Given there are such differences, and these differences show up differently in different years (compare 2013 to 2015), why should we be so sure that the differences in Georgia 2017, for example, are due to the treatment? To put it another way, they seem to be leaning very heavily on the comparisons to the matched tracts.

That said, there’s a lot about these data I don’t understand. Like, why do registrations increase steadily within each year? I’m sure there’s a reason, and maybe it’s in the report and I didn’t see it.

The authors write:

We were able to isolate the effect of AVR using a common political science method known as “matching.” We ran an algorithm to match areas that imple- mented AVR with demographically similar jurisdictions that did not. Matching similar jurisdictions allowed us to build a baseline figure of what a state’s registration rate would have looked like had it not implemented AVR.

That’s all fine but it doesn’t really address these data issues.

McElwee wrote his own critique of the Morris and Dunphy study, focusing on the difference between “back end” and “front end” registration systems. You can follow the link for details on this.