I've noted some confusion in discussions with reporters recently, and I have to assume that this confusion is somewhat widespread. The issue is whether or not a "paper trail" resolves the problems with electronic voting. The term "paper trail", in my opinion, is an unfortunate one. When I first got seriously involved in this issue in 2003, many of us advocated paper trails as a solution to paperless DREs. The thinking was that if every vote is recorded on a piece of paper and that paper was audited by the voter, then a correct tally could be produced by counting the papers. This could be used to audit the machines, or as the definitive ballots. In theory, this seems reasonable, but it doesn't work in practice, and the theory is a bit flawed as well.
As I describe this, keep in mind that the underlying premise is that the software-only DREs should not be trusted. Software often fails in unexpected and unexplainable ways, and in the case of national public elections, there is a threat that the software could have been rigged or modified, or just be plain old buggy. The bottom line is that elections are more trustworthy if we don't have to trust the software. So, given that premise, paper trails only provide some benefit if the papers are actually counted. Otherwise, the machines are just as vulnerable as ones that don't have paper trails. Unless there is a policy for checking the ballots, and unless voters actually inspect the paper trails, we might as well just use DREs because the paper trails are useless under those circumstances. In practice, things are actually worse. Vendors have developed paper trails that are unwieldy, difficult to count, printed with fading ink, and prone to failure and paper jams.
All of my experience with paper trails on DREs leads me to believe that instead of "paper trails" what we need are "paper ballots". In paper ballot systems, ballots are produced as in traditional elections, and these are the official ballots of record. By using touch screen ballot marking devices to create paper ballots (or even allowing people to mark them by hand), we avoid all of the problems of the paper trails. We end up with ballots that can be counted multiple ways, and which provide tangible evidence of the intent of each voter.
So, my advice is to abandon the term "paper trail", to abandon DREs with paper trails, and to start talking about paper ballots.
