Optical scan is a voting method that uses electronic technology to tabulate paper ballots. An optical scan voting system is made up of computer-readable paper ballots, appropriate marking devices (writing instruments), privacy booths, and a computerized device that reads and tabulates the ballots. Optical scan ballots are marked using an appropriate writing instrument to fill in boxes or ovals, or to complete an arrow next to a candidate’s name or an issue.
How it works Edit
To cast the ballot, voters deposit their ballots into a sealed box to be counted either at the polling place — a precinct count optical scan — or at a central location — a central count optical scan. The ballots are tabulated by optical-mark-recognition equipment, which counts votes by sensing or reading the marks on the ballot. Software instructs the tabulation equipment how to assign each vote (i.e., to assign valid marks on the ballot to the proper candidate or issue).
If ballots are counted at the polling place, voters or election officials put the ballots into the tabulation equipment, which tallies the votes; these tallies can be captured in removable storage media that are transported to a central tally location, or they can be electronically transmitted from the polling place to the central tally location. Some precinct-based optical scanners also now include a digital ballot imaging component that digitally reads a voter’s ballot selection, tabulates the results, and saves a digital image of the marked ballot on a memory card for auditing purposes.
In addition, precinct-based optical scanners can be programmed to detect overvotes and undervotes (where the voter does not vote for all contests or issues on the ballot) and to take some action in response (such as rejecting the ballot). If election officials program precinct-based optical scan systems to detect and reject overvotes and undervotes, voters can fix their mistakes before leaving the polling place.
By contrast, if ballots are centrally counted, election officials transfer the sealed ballot boxes to the central location after the polls close, where election officials run the ballots through the tabulation equipment in the presence of observers. Central count optical scanners thus do not allow voters to correct any mistakes that may have been made.