The recount of the 2008 Minnesota Senate race gives us an opportunity to evaluate the accuracy of precinct-count optical-scan voting. Though there have been contentious disputes over which absentee ballot envelopes to open, the core technology for scanning ballots has proved to be extremely accurate.

The votes were counted by machine (except for part of one county that counts votes by hand), then every single ballot was examined by hand in the recount.

The “net” accuracy of optical-scan voting was 99.99% (see below).
The “gross” accuracy was 99.91% (see below).
The rate of ambiguous ballots was low, 99.99% unambiguous (see below).

My analysis is based on the official spreadsheet from the Minnesota Secretary of State. I commend the Secretary of State for his commitment to transparency in the form of making the data available in such an easy-to-analyze format. The vast majority of the counties use the ES&S M100 precinct-count optical-scanners; a few use other in-precinct scanners.

I exclude from this analysis all disputes over which absentee ballots to open. Approximately 10% of the ballots included in this analysis are optically scanned absentee ballots that were not subject to dispute over eligibility.

There were 2,423,851 votes counted for Coleman and Franken. The “net” error rate is the net change in the vote margin from the machine-scan to the hand recount (not including change related to qualification of absentee ballot envelopes). This was 264 votes, for an accuracy of 99.99% (error, one part in ten thousand).

The “gross” error rate is the total number of individual ballots either added to one candidate, or subtracted from one candidate, by the recount. A ballot that was changed from one candidate to the other will count twice, but such ballots are rare. In the precinct-by-precinct data, the vast majority of precincts have no change; many precincts have exactly one vote added to one candidate; few precincts have votes subtracted, or more than one vote added, or both.

The recount added a total of 1,528 votes to the candidates, and subtracted a total of 642 votes, for a gross change of 2170 (again, not including absentee ballot qualification). Thus, the “gross” error rate is about 1 in 1000, or a gross accuracy of 99.91%.

Ambiguous ballots: During the recount, the Coleman and Franken campaigns initially challenged a total of 6,655 ballot-interpretation decisions made by the human recounters. The State Canvassing Board asked the campaigns to voluntarily withdraw all but their most serious challenges, and in the end approximately 1,325 challenges remained. That is, approximately 5 ballots in 10,000 were ambiguous enough that one side or the other felt like arguing about it. The State Canvassing Board, in the end, classified all but 248 of these ballots as votes for one candidate or another. That is, approximately 1 ballot in 10,000 was ambiguous enough that the bipartisan recount board could not determine an intent to vote. (This analysis is based on the assumption that if the voter made an ambiguous mark, then this ballot was likely to be challenged either by one campaign or the other.)

Caveat: As with all voting systems, including optical-scan, DREs, and plain old paper ballots, there is also a source of error from voters incorrectly translating their intent into the marked ballot. Such error is likely to be greater than 0.1%, but the analysis I have done here does not measure this error.

Hand counting: Saint Louis County, which uses a mix of optical-scan and hand-counting, had a higher error rate: net accuracy 99.95%, gross accuracy 99.81%.

Louisiana held a Congressional primary election on October 4th, 2008. In the 4th-Congressional-district Democratic Primary, there were four candidates; the two candidates with the most votes advanced to the runoff. The margin between the second (advancing) candidate and the third (nonadvancing) candidate was 1,484 votes. But, as I will explain, at least 2,167 voters, and probably more than 5,000 voters, were wrongly prevented from voting in the Democratic primary. This disenfranchisement appears to result from incorrect or unclear instructions given by the Secretary of State to the pollworkers at all the individual precincts.

In Louisiana the Republican Party held a closed primary; that is, only those voters registered as Republicans could vote. The Democratic Party held an open primary; that is, the party allowed Democratic and Independent voters to vote in the Democratic congressional primary. Members of the Green Party, Reform Party, and Libertarian Party were not permitted to vote in the Democratic Primary. However, there were some races on the ballot other than the Congressional Primary election: for example, any voter in Shreveport could vote in the election for City Marshal.

On election day there were reports that when Independent voters pressed the button on the voting machine for a candidate in the Democratic congressional primary, nothing happened. In effect, these voters said that they were prevented from voting in the Democratic Congressional primary. This did not conform to the election law, because it did not respect the Democratic Party’s choice to hold an open primary.

Caddo Parish, in the 4th Congressional district, uses Sequoia AVC Advantage version 9.00H direct-recording electronic voting machines. I am very familiar with this model of voting computer, since I performed an in-depth study of these machines in New Jersey. The way these AVC Advantage voting computers work in a Louisiana primary election is this: Each voter, when he or she signs in to vote, is handed a ticket. The ticket indicates which primary election the voter is entitled to participate in. When the voter hands this ticket to the Commissioner (pollworker) who stands by the voting machine, the Commissioner presses an “option switch” button that selects which contests on the ballot that voter is permitted to vote in. The “option switch” button is sometimes called a “lockout” button, because it “locks out” some contests from the voter. For example, if the voter hands in a ticket marked REPUBLICAN, the Commissioner presses a REPUB lockout button. Then the Democratic primary ballot is “locked out” (so those buttons have no effect), and the Republican primary ballot is active. Or, if a registered Democrat approaches the polls, he or she gets a ticket marked DEMOCRAT: the operator pushes the DEM lockout button. This locks out the Republican primary ballot, and activates the Democratic primary ballot. Finally, a registered voter in the Green Party, Reform Party, or Libertarian party gets a ticket marked “No Party.” The Commissioner then presses the option switch marked “Others.” This locks out both primary ballots, so this voter can vote only in contests such as City Marshal.

With this combination of technological setup plus election law, it is clear that the pollworkers at the sign-in desk should hand Independent voters a ticket marked “DEMOCRAT.” Only this way can they vote in the Democratic primary. It won’t do to hand them a ticket marked “No Party” and then have the Commissioner press the “DEMOCRAT” button, because this solution won’t properly handle the Green, Reform, and Libertarian voters. So the question is, “Did the Secretary of State effectively instruct and train the Commissioners so that Independent voters were permitted to vote in the Democratic Primary?” He did not, as I will show.

When the polls are closed, the AVC Advantage prints out a paper tape (like a cash register tape) listing how many votes each candidate got. But in addition the computer prints out a list of “Option Switch Totals”, indicating how many voters were permitted to vote in each of the primary elections on the ballot. That is, the “Option Switch Totals” show how many times the Commissioner pressed each one of the the “DEM”, “REPUB”, and “Others” buttons.

On October 15th, 2008 I visited Caddo Parish’s voting-machine warehouse in Shreveport. I examined all the paper-tape “results report” printouts from the approximately 400 voting machines used in the entire Parish (a parish in Louisiana corresponds to a county in other states). I added up how many voters voted with the “Other” option-switch setting. All of these voters were “locked out” of both the Democratic and Republican Congressional primaries.

In all, 2,167 voters in Caddo Parish voted with the Other option switch. These voters were not able to record a vote in either the Democratic or Republican party primary, that is, they were “locked out” of voting in the Democratic Congressional Primary. The vast majority of these 2,167 locked-out voters are Independents, because Party registration for the Green Party, the Libertarian Party, and Reform Party is negligible. For example, the Green Party has only 1,064 registered voters in the entire State of Louisiana (7 Congressional districts). In contrast, there are about 80,000 Independent voters in the 4th Congressional district alone. Thus, almost all of the 2,167 voters in Caddo Parish who were locked out were almost certainly Independents.

Some independent voters approached the polls and were told that independent voters were not permitted to vote in the Democratic Congressional Primary. Some of these voters left the polling place without signing in to vote. These voters were disenfranchised as well, in addition to the 2,167 that we can count in the option-switch numbers.

Caddo Parish contains about 40% of the voters of the entire 4th Congressional district. If the same proportion of Independent voters were locked out of the Democratic primary in the other parts of the district, that means that more than 5,000 Independent voters were illegally disenfranchised from voting in the Democratic primary. Since the margin between winning and losing candidates was 1,484, that means the number of disenfranchised voters was larger than the margin of victory. Those voters could have changed the outcome of the election, if they had been lawfully permitted to vote.

Louisiana holds its runoff primary election (for both parties) on November 4th. Once again, the Democratic Party is holding an open primary, and the Republican Party is holding a closed primary. I urge the Secretary of State of Louisiana to give clear instructions to Commissioners of precincts, as follows:

“Independent voters are to be given a ticket marked DEMOCRAT. Democratic voters are to be given a ticket marked DEMOCRAT. Republican voters are to be given a ticket marked REPUBLICAN. Green Party, Reform Party, and Libertarian Party voters are to be given a ticket marked NO PARTY.”