When voters in Alameda and Santa Clara County head to the polls on Nov. 6, about one percent will cast their ballots on electronic voting machines that have known security vulnerabilities. California has safeguards in place. In addition to requiring paper records for votes cast on electronic machines, California also manually audits one percent of all ballots cast, to make sure there’s no discrepancy in the numbers. Now, experts like David Dill, a computer science professor at Stanford and founder of Verified Voting, are saying that isn’t enough, and are pushing states like California to implement more rigorous auditing methods. “The problem of protecting machines is pretty unmanageable, even with the best and most modern hardware … so what you need to do is select a bunch of ballots at random and hand count them in order to make sure the electronic counts are accurate,” says Dill.
What Dill suggests instead is something called a risk-limiting audit — an incremental recount that continues until there’s strong evidence that counting additional ballots would simply confirm the recorded results.
Although this sounds like more work, Philip Stark, associate dean of Mathematical and Physical Sciences at UC Berkeley, says risk-limiting audits often involve fewer ballots than traditional auditing methods.
If California adopted risk-limiting audits for all contests, we would end up looking at fewer ballots than we do right now, but we would look at them chosen in a different way, and we’d make an intelligent decision about when to stop,” he says.
Risk-limiting audits are currently being piloted in Orange County and are run state-wide in Colorado.