Voting Machines Explained
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A Brief Primer on Electronic Voting Equipment

Electronic voting systems come in three distinct flavors. Here is a very brief overview of each.

Direct Recording Electronic (DRE) equipment

A DRE machine is a computer with a screen for displaying ballots and a keyboard or touchscreen through which the voter marks the ballot. The ballot can be displayed on a single screen (if the screen is large enough), in which case it is called a full-face ballot, or on a sequence of screens. A DRE machine can be made accessible to voters with various disabilities through the addition of alternative mechanisms for displaying and marking the ballot. These include audio response units for use by the blind and puff tubes for those with impaired motor skills.

In a DRE machine, the voter verifies the image that is displayed on the screen. After the ballot is cast, an electronic form of the ballot is stored inside the machine. While inside the machine, it is under the complete control of the software running on the voting machine. There is no way to verify that the electronic form of the ballot agrees with the screen(s) that captured the voter's intent. If the electronic record is later damaged or lost for any reason, there is no way to recover the voter's intent or to perform a meaningful recount.

DRE with Voter-Verified Paper Ballot Printer (DRE+VVPB)

A DRE+VVPB machine adds a ballot printer to a basic DRE machine. After the voter marks the ballot, the ballot is printed out behind a glass panel and the voter is given the opportunity to verify its correctness. If the voter accepts it as correct, the voter's selections are stored internally, just as with an ordinary DRE machine, but in addition, the voter-verified paper ballot is automatically placed in a locked ballot box. After the polls close, paper ballots from a random sampling of voting machines can be hand-counted as a check on their correct operation. The paper ballots also serve as a backup in case the electronic versions of the ballots become damaged or lost, and they become the official record of voter intent in case a recount is required.

Precinct Optical Scan Systems

In a precinct optical scan system, the voter marks a paper ballot, either with a pen or with the assistance of a computerized ballot marking device. The voter then inserts the marked ballot into a scanner, which reads the ballot and displays it to the voter for verification. It also warns the voter of overvotes and undervotes for any office. If any problems are detected, the voter has the option of requesting a new ballot and starting over. After the polls close, the ballots are optically counted, either at the precinct level or centrally. In case of a recount, the ballots can be rescanned by the same or different scanner, or they can be counted by hand.

A ballot marking device allows voters with various disabilities to mark the paper optical scan ballots without assistance. It is similar to a disabled-accessible DRE machine except that the voter's selections are not recorded internally but are instead printed on a ballot form suitable for optical scan. After the ballot is marked, the voter inserts it into a scanner for verification, just as one does with a hand-marked ballot. In either case, the ballot is checked for readability and other problems and the voter is given the opportunity to request a new ballot. Like the ballot marking device itself, the scanner is made accessible to the disabled by being equipped with an audio response unit and other accessibility mechanisms.

A Brief Comparison of Voting System

Accessibility and HAVA Compliance
All three systems meet the Help America Vote Act (HAVA) requirements for private unassisted voting by the disabled.
Auditability and Recounts
DRE+VVPB and optical scan systems both maintain paper records of the voter's intent. The paper allows for verification of the voting system and for recounts when required. DRE machines do not preserve any voter-verified record of voter intent and thus provide no means for auditability and recounts.
Optical scan systems are more transparent to voters and poll workers because ballot marking and vote tabulation are easily-understandable separate steps performed by different devices.
Optical scan systems use the same paper ballots for ballots cast at a polling place and for absentee ballots. The two DRE options are unable to accommodate absentee voting, so paper ballots must still be printed and counted for use by absentee voters.
Optical scan systems are likely to be considerably less expensive than either of the DRE options. This is because enough DRE machines must be provided to accommodate every voter, whereas most voters can mark optical scan ballots by hand, requiring only a pen and a privacy booth.
Last modified: Sun Nov 20 16:42:58 EST 2005 email to webmaster: Alice Fischer