April 14, 2024

New Study of E-Voting Effects in Florida

Yesterday, a team of social scientists from UC Berkeley released a study of the effect of e-voting on county-by-county vote totals in Florida and Ohio in the recent election. It’s the first study to use proper social-science modeling methods to evaluate the effect of e-voting.

The study found counties with e-voting tended to tilt toward Bush, even after controlling for differences between counties including past voting history, income, percentage of Hispanic voters, voter turnout, and county size. The researchers estimate that e-voting caused a swing in favor of Bush of up to 260,000 votes in Florida. (A change of that many votes would not be enough to change the election’s result; Bush won Florida by about 350,000 votes.)

No e-voting effect was found in Ohio.

The study looks plausible, but I don’t have the expertise to do a really careful critique. Readers who do are invited to critique the study in the comments section.

Regardless of whether it is ultimately found credible, this study is an important step forward in the discourse about this topic. Previous analyses had shown differences, but had not controlled for the past political preferences of individual counties. Skeptics had claimed that “Dixiecrat” counties, in which many voters were registered as Democrats but habitually voted Republican, could explain the discrepancies. This study shows, at least, that the simple Dixiecrat theory is not enough to refute the claim that e-voting changed the results.

Assuming that the study’s authors did their arithmetic right, there are two possibilities. It could be that some other factor, beyond the ones that the study controlled for, can explain the discrepancies. If this is the case, we can assume somebody will show up with another study demonstrating that.

Or it could be that e-voting really did affect the result. If so, there are several ways this could have happened. One possibility is that the machines were maliciously programmed or otherwise compromised; I think this is unlikely but unfortunately the machines are designed in a way that makes this very hard to check. Or perhaps the machines made errors that tended to flip some votes from one candidate to the other. Even random errors of this sort would tend to affect the overall results, if e-voting counties different demographically from other counties (which is apparently the case in Florida). Another possibility is that e-voting affects voter behavior somehow, perhaps affecting different groups of voters differently. Maybe e-voting scares away some voters, or makes people wait longer to vote. Maybe the different user interface on e-voting systems makes straight party-line voting more likely or less likely.

This looks like the beginning of a long debate.


  1. John Thacker says

    As noted by Crooked Timber, essentially the entire effect is driven by the results in Broward and Palm Beach County.

    There’s something particularly odd about the Palm Beach County results from 2000, anyway. It was practically the only county in FL where Bush ran underneath the vote totals of Bill McCollum, the Republican candidate for Senate who lost to Bill Nelson. See the results here, for example. It also had a strangely high number of overvotes and missed votes in 2000. In 2004 Bush ran ahead of Martinez in Palm Beach County, just as he did elsewhere in the state.

    Of course, there can be other reasonable explanations for it (perhaps the Jewish vote swung a bit in those counties between 2000 and 2004) but it is interesting.

    As Crooked Timber rightly points out, even a technically statistically significant effect can be suspect if it is significant based entirely on one or two pieces of data out of many.

  2. Well, the ability of various e-voting machines to change voter behaviour will depend on the particular e-voting machine.

    For instance, here in NC, half of the counties have e-voting machines that look something like ATMs. You get black buttons on the sides of a low-res LCD screen. The candidates are listed with lots of white space between them, and you push the button that corresponds to your choice for each office. This machine makes it very easy to vote straight-ticket. However, the buttons may be hard for some people to press, and the screen might be hard for people with poor eyesight. I understand that the election officials are supposed to help people with difficulty working these machines. In all, I believe that “voter fatigue” is less likely with this machine.

    Touch-screen voting machines have pictures and all sorts of whiz-bang doo-dads. Although I’ve seen these machines, I haven’t used one in voting, so I can’t say how it would affect me (as an average voter). I would be interested in an opinion from somebody who’s actually been exposed to this kind of machine.

    Of course, the question is which kind is used in Florida and Ohio.

  3. While you crunch away at the numbers, be sure and examine just how effective the Republican Party has been in reshaping the electorate. They have regained control of the Senate in a way not seen since prior to the New Deal. When the Democrats reject their current tactics, they may just win a few elections again.

  4. Here’s an analysis at Crooked Timber, with links to other work, too.

  5. Occam’s Razor doesn’t let you know whether explanatory variables were omitted from your model. Given the stakes, you can bet that this *will* produce a debate.

    It’d be interesting, for example, to know what accounts for variations in the magnitude (or existence!) of the e-voting effect.

  6. This looks like the beginning of a long debate

    This sounds to me like debating how many angels can fit on the head of a pin. Would we need it if the machines produced paper ballots records? (Maybe, but given that there’s a discrepancy in only the evoting counties, can’t we just apply Occam’s Razor?)