The Raleigh News and Observer reports that the Republicans are planning to introduce a bill to require photo ID before voting. The Republicans are arguing that this will reduce voter fraud and increase faith in the system. The Democrats will likely argue that this will reduce voter turnout--particularly among less educated and minority populations. So--what does the empirical evidence suggest about this debate?
There is very little evidence of voter fraud. As the N&O article points out, there were 18 documented cases of double-voting in NC in 2008 and I've seen similarly small numbers reported in Georgia. The NY Times reports very small incidents of voter fraud from a multiple-state study (see also here). I have not seen any reputable study that documents widespread voter fraud in the last 20 years (see, in particular, this book). Unless this research is missing something, it doesn't appear that voter fraud is a widespread problem.
There is some (very limited and contested) evidence that voter ID laws suppress turnout. Vercellotti and Anderson document a small decrease in turnout when voter ID laws are put into place. In perhaps the most sophisticated study to date, researchers from Cal-Tech (can you say Baysian multi-level analysis? Me neither) investigate the range of potential restrictions* and come to a similar conclusion: voter ID laws result in a small decrease in voter turnout. These findings are not uniform, however. A team of researchers from the University of Delaware found no effect of voter ID laws on turnout and Columbia's Robert Erikson and his colleague replicate this small (~2 point) effect, but note that it is "statistically inconclusive" and that "the data that have been analyzed to date do not allow a conclusive test." Sometimes science is frustrating.
There is some (very limited and contested) evidence that voter ID laws suppress turnout among people with lower socio-economic status. Minorities and the elderly (two groups who traditionally vote Democratic) are the least likely to have DMV issued photo IDs. From this, you would expect that these groups would be negatively influenced by photo ID laws. And some studies have documented a larger turnout decline among minority and less educated voters, but others remain more skeptical. The Cal-Tech group does not find that minorities are any more disadvantaged than other groups, but they do find that lower income folks and the elderly are comparatively more disadvanaged by voter ID laws. Again--a mixed bag of findings.
There is little evidence that voter ID laws increase trust in the electoral system. Harvard's Steven Ansolabehere (say that three times fast) finds that there is no relationship between the frequency of electoral fraud and whether someone votes. He also finds that "voters living in states with stricter identification laws did not report higher levels of confidence or higher rates of voting than those living in states with relatively weak identification rules." In other words, if we pass this law in NC, it probably won't give people more faith in the system or increase voter turnout.
Unfortunately the science here doesn't tell us unequivocally that voter ID laws are a good or bad thing. I think if anything, the evidence suggests that we should be skeptical of both sides. When Republicans say that fraud is rampant or that voter ID laws will increase trust in the system, be skeptical. Likewise, when Democrats say that voter ID laws will depress turnout in large and meaningful ways and that turnout will go down particularly strongly among low SES voters, be skeptical.
*Here are the possible rules, according to Alvarez and colleagues:
- Voter must state his/her name
- Voter must sign his/her name in a poll book
- Voter must sign his/her name in a poll book and it must match a signature on file
- Voter is requested to present proof of ID or voter registration card
- Voter must present proof of ID or voter registration card
- Voter must present proof of ID and his/her signature must match the signature
on the ID provided
- Voter is requested to present photo ID
- Voter is required to present photo ID.