Ask the Expert

The role of computers in voting should be limited, because computers are fundamentally limited machines. Computers are so complex that we can’t tell whether they are working properly. Because of system errors and the possibility of tampering, we may never have a computerized voting system that we can deem completely trustworthy. Any electronic voting system should therefore include a paper ballot that voters can verify and a system of auditing in which paper ballots and electronic vote counts can be compared. For a democracy to be successful, it not only needs elections that are accurate but also ones where people believe in the results, even if they are unhappy with them. People often refer to this desired combination of accuracy and credibility as “transparency.” A good analogy explains this word choice and points out the problem with all-electronic voting systems:

Imagine a voting system in which you walked into a booth and dictated your votes to a man hidden behind a curtain. The job of the man would be to write your votes down and put them into a ballot box. Without the ability to see the man (the curtain is not transparent) how could you be sure that he was writing down your votes accurately? How could you be sure that he really put your ballot into the ballot box so that it would be counted? All-electronic voting systems are just as lacking in transparency. There is no way for the voter to verify that the vote was recorded properly or that it was stored for counting.

The computer is just like the man behind the curtain. Software can programmed accidentally or intentionally to do the wrong thing. You can’t see what is happening inside the computer.  It can even show you one vote while recording another.

A much better system is the one that is already used in many parts of the country. Voters  fill out a paper ballot, so they can see their physical markings right on the page. Then they feed the ballot into a machine that optically scans it and collects it. This way, voters can  see their  ballots going into authorized equipment. You might say, however, that the scanner could still make an error or be hacked and you’d be right. But in California, by law, one percent of voting precincts are selected at random and subjected to an audit where the paper ballots and electronic counts are compared. Discrepancies are investigated and reconciled to arrive at a  count that everyone can believe.

Today 13 states require such audits and more than half of the states require a paper trail for electronic votes. It didn’t used to be that way. When I got involved in the debate on electronic voting in 2002, and founded the non-profit, non-partisan VerifiedVoting.org, only one state required audits. Many states were instead naively charging ahead with all-electronic voting. Unfortunately until computer scientists joined in a campaign against the practice, the people making policy decisions were lacking good technical advice.

I’m very aware of the limits of computers in voting because of my research into the limits of computers. I work on methods for verifying the correctness of systems such as circuits, network protocols and software programs. What I and my colleagues in the field have found is that while we can improve these methods, we cannot perfect them (especially because all of these systems are rapidly gaining in complexity). I’m a computer scientist because I love computing, but it needs to be used appropriately.