Note that the Prime III software runs on a bootable DVD; therefore, the software can't be changed once it has been burned to disc. If the voter needs assistance entering the booth, the poll worker or necessary individual(s) can help the voter. Inside the voting booth, the voter will use the touch screen and/or the headset, to cast her/his votes. Note that the voter can choose to use either the touch screen and/or the voice enabled headset and/or an A/B switch (see figure 1) with the headset at any point during the voting process; hence, the interface is multimodal. The left side of the A/B switch does selection or enter and the right side does next or continue. The voter is not required to select voice or touch. S/he can simply use it throughout interchangeably as desired. The Prime III system cannot distinguish a blind voter from a sighted, deaf or any other type of voter. Everyone is voting on the same machine. For voters using the touch screen, Prime III uses large fonts with neutral colors, see figure 2.
Figure 1: Prime III A/B switch
Figure 2: Sample Prime III screen
Note that each contest lists the candidates in a single column. This ballot design removes ambiguity and confusion by only showing the candidates for one contest at a time where other systems show multiple candidates per screen, which in most cases is simply copying the paper ballot to the screen. Paper to screen voting systems are bad design practices.
When a voter uses the headset to vote, s/he will receive prompts that speak the ballot options currently displayed. If the choices are Mickey Mouse, Optimus Prime, Bugs Bunny and Elmer Fudd; Prime III will prompt the user with something similar to “To vote for mickey mouse, say vote <beep> (1.5 second pause) to vote for optimus prime, say vote <beep> (1.5 second pause) to vote for bugs bunny, say vote <beep> (1.5 second pause) ... ”. The voter will wait until their candidate's name or option is spoken and say vote after the prompt or blow into the microphone. Prime III also allows for the voter to simply blow into the microphone after the prompt during the 1.5 second pause to make selections as well. As such, eavesdroppers will hear a voter saying vote or nothing at all without any indication of the voter’s choices. Note that this is different from other voting systems by which the voter either hears the options and then uses Braille coded buttons to make their intent known or the voter uses a human proxy to record their votes. To our knowledge, Prime III is the only voting system to take full advantage of a speech interface allowing hands free, eyes free interaction. Individuals that can't see, hear, read, don't have hands, etc. can all vote privately and independently using this multimodal interface on the same equipment as those that do not have any disabilities. During voting, the voter will be required to confirm her/his ballot twice. After the second confirmation, the voter’s ballot will be printed with the options the voter selected. This is called the voter-verified & generated ballot (VVGB), see figure 3.
Figure 3: Voter-Verified & Generated Ballot (VVGB)
Figure 4: Voter-Verified & Generated Ballot (VVGB) with identification number
After the VVGB is created, it is scanned by the Tally Machine, which is a second independent machine, using optical character recognition (OCR). Notice that this method of reading the ballot content via OCR resembles how humans will count the ballot. In modern optical scan machines, the tally machines read ovals or arrows; however, when people audit those ballots, they can come to a very different interpretation of the voter's intent because people count by reading the name, not the oval or arrows. This is especially true for write-in candidates. In the Prime III model, we require a manual statistical audit to confirm the tabulation machines' results. If the results are inconsistent with the manual statistical audit (see figure 5), this will require an immediate manual recount of all the ballots. Note that the VVGB will eliminate ambiguous marks that occur on optical scan ballots (click here to see Minnesota sample ballots or click here to see write-in samples from Alaska); therefore, the voter's intent is clearly indicated on each ballot yielding quick and easily verified results. Another option for this process is to place the VVGB into a ballot box and later place an identification number on each ballot to uniquely identify each ballot. Note that this occurs after the ballots have been placed into the ballot box, therefore, this does not attach any voter to a ballot. The identification number will provide benefits for auditing the election, i.e. single ballot audits to confirm the tally machine's image of a ballot matches the physical/paper ballot.
Figure 5: Statistical Power of Audits
Prime III employs a multimodal user interface that gives voters from all segments of the population equal, private and independent access to participate in the electoral process. All voters verify their ballot the same way, regardless of ability. Prime III implements security using a voter-verified and generated ballot (VVGB) with a mandatory statistical manual audit. Prime III uses a usable security model that incorporates usability and security throughout the design, implementation and evaluation of our prototype. This is an accessible, software indepenent approach to voting.
Percentage-Based versus Statistical-Power-Based Vote Tabulation Audits John McCarthy , Howard Stanislevic , Mark Lindeman , Arlene S . Ash , Vittorio Addona , Mary Batcher The American Statistician Feb 2008, 62, 1, pp. 11 –16.