An Analysis of Write-in Marks on Optical Scan Ballots

Optical scan ballot systems are widely used in elections today. However, deployed optical scan systems may not always interpret write-in votes correctly. For instance, if a voter writes in a name but forgets to shade in the corresponding voting target, an optical scanner may not detect the write-in, which could lead to a lost vote. In this paper, we study methods for automatic recognition of write-in marks. We then apply these methods to ballots from an election in Leon County, Florida and study the kinds of write-in marks that are seen in practice. Our results from this election show that voters frequently (about 49% of the time) do not fill in the write-in bubble when entering a write-in vote. Consequently, votes may be lost in current voting systems.