Mike Alvarez, Delia Bailey, and Jonathan Katz just completed this paper:
Since the passage of the “Help America Vote Act” in 2002, nearly half of the states have adopted a variety of new identification requirements for voter registration and participation by the 2006 general election. . . . In this paper we document the effect of voter identification requirements on registered voters as they were imposed in states in the 2000 and 2004 presidential elections, and in the 2002 and 2006 midterm elections. Looking first at trends in the aggregate data, we find no evidence that voter identification requirements reduce participation. Using individual-level data from the Current Population Survey across these elections, however, we find that the strictest forms of voter identification requirements — combination requirements of presenting an identification card and positively matching one’s signature with a signature either on file or on the identification card, as well as requirements to show picture identification — have a negative impact on the participation of registered voters relative to the weakest requirement, stating one’s name. . . .
It looks interesting to me. It’s a hard problem to study because the number of states with changes is not large. Also, I’m still a little baffled by Figures 5 and 6, where it says that Pr(voting) > 90% for “an average registered voter”. Turnout isn’t really that high! I thought it was closer to 70%? Perhaps something was set to zero rather than the middle of the distribution when computing the average? It shouldn’t make a difference for the comparison but it would be good to get that intercept settled to a reasonable value. One thing that would also help would be to plot the raw data on top of some of these graphs to make sure the model is doing what it’s supposed to be doing.
I was also suspicious that in Figure 6, the confidence intervals have the same width for nonwhite as for white respondents. There are fewer nonwhites, so I’d think their confidence intervals should be wider. But since the model has no interactions, I guess it makes sense for the confidence intervals to have the same with here. Also, I’d take Figures 7-9 and make them as one figure with 8 columns and 3 rows, this would allow easier comparisons.