How Do Electronic Voting Machines Work?

A working at a voting location doing some maintenance on a voting machine.

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There are two main types of electronic voting machines: optical scan systems, and direct recording electronic (DRE) systems. The difference is that optical scan systems use paper ballots, which are scanned and tabulated electronically, while DRE systems require you to vote using a machine.

All optical scan systems work in basically the same way, and the only major differences are the type of mark you need to make on the ballot, and whether or not you scan your own ballot. States that use vote-by-mail systems use optical scan electronic voting, and absentee ballots are typically also cast using this technology.

Direct recording electronic voting systems are more complicated, because there are so many different types. The three main types of DRE voting machines use touchscreens, push-buttons, and dials to register votes. While there are only a few companies that make DRE voting machines, there are dozens of different models in service.

How Optical Scan Electronic Voting Systems Work

Optical scan electronic voting systems have been around longer than any other electronic voting systems. They work via the same optical scanning method used by many standardized tests, so if you ever took a standardized test in school, you're probably already familiar with this process.

Here's how the voting process works if your precinct uses an optical scan voting system:

  1. Upon arrival at your polling place, a poll worker will verify your voting status and provide you with an appropriate ballot.
  2. Take your ballot to an available voting station, as directed by local volunteers or workers.
  3. Mark your ballot as directed.
    1. Important: Take great care to read any instructions on the ballot and use the suggested method. For instance, if the ballot says to fill in a bubble, do not place a check or cross in the bubble. If you don't follow the correct procedure, your ballot may not be counted.
  4. When you are done voting, follow the instructions of local poll workers.

Note: You may need to scan your ballot yourself by inserting it into a scanning machine, or you may need to place it in a lockbox for poll workers to scan at a central location.

How Touchscreen Electronic Voting Systems Work

Touchscreen electronic voting machines work a lot like smartphones and tablets. The ballot is displayed on a touchscreen LCD along with an interface or controls. There may be physical buttons in addition to the touchscreen, or the DRE may be operated entirely via the touchscreen.

While touchscreen DRE machines all work in basically the same way, each one has a specific procedure that you need to follow.

Volunteers at your polling place will be able to instruct your further, but as an example, here's how to use the common Premier AccuVote TS:

  1. Upon arrival at your polling place, a poll worker will verify your voting status and provide you with a smartcard.
  2. Approach an available voting machine, as directed by poll workers, and insert your smartcard into the machine.
  3. Follow the on-screen prompts to register your votes.
  4. When the process is complete, the smartcard will pop out of the machine with an audible click.
    1. Note: In some cases, a paper ballot will print at this time. If your polling place has this feature, you will be able to view the ballot inside the housing of the voting machine. Examine the ballot and verify that the machine correctly registered your votes.
  5. Return the smartcard to a poll worker.

Most touchscreen DRE voting machines use this same general procedure. In some cases, the smartcard does not store your preferred language, in which case you will need to select a language on the machine before you start voting.

In other cases, you will not receive a smartcard at all. Instead, the poll worker will typically walk you to an available machine and activate it for you.

Although most touchscreen DRE machines rely entirely on the touchscreen interface, some have physical controls that you can use as a backup. You may also need to push a physical button, usually marked with the word vote, to complete the voting process.

Some machines also give you the option to mark your ballot as spoiled, and then cast another ballot, if the choices marked on the paper ballot don't match the choices you meant to make. In other cases, you will need to alert a poll worker to the discrepancy.

Touchscreen DRE voting machines used in the United States include:

  • Sequoia AVC Edge/Edge II – Used statewide in Nevada, and in areas of Arizona, California, Colorado, Illinois, Missouri, and Wisconsin.
  • Avante Vote-Trakker – Some areas of New Jersey.
  • Danaher Shouptronic 1242 – Statewide in Delaware, and some areas of Pennsylvania, Tennessee, and Arkansas.
  • ES&S iVotronic – Some areas of Arkansas, Colorado, Washington DC, Kansas, Missouri, North Carolina, Ohio, West Virginia, and Wisconsin.
  • Premier AccuVote TS/TSX – Statewide in Alaska, Georgia, and Utah, and some areas of Arizona, California, Colorado, Florida, Illinois, Indiana, Kansas, Kentucky, Mississippi, Missouri, Pennsylvania, Ohio, Tennessee, Texas, Wisconsin, and Wyoming.
  • UniLect Patriot – No longer in use.
  • AVS Winvote/Winscan – No longer in use.

How Push-Button Electronic Voting Systems Work

Push-button electronic voting machines can use both paper ballots, digital readouts, and LCD screens, depending on the particular system. The one thing that they share in common is that the candidates and measures are all displayed next to physical buttons. By pressing the button next to your choice, the machine registers your vote.

Voting machines that use push-button interfaces all require you to push physical buttons to register your votes, but each has some specific steps that you'll need to follow.

Volunteers at your polling place will be able to instruct your further, but as an example, here's how to use the Sequoia AVC Advantage:

  1. Upon arrival at your polling place, a poll worker will verify your voting status and provide you with a voting ticket.
    1. Note: The voting ticket is a colored piece of paper that contains two identical numbers that are unique to your specific ticket. Do not lose the ticket.
  2. Approach an open voting machine, as directed by poll workers or signage, and hand your voting ticket to the poll worker assigned to that machine.
  3. The poll worker will prepare the voting machine, tear your ticket in half, and hand one piece back to you.
  4. Enter the curtains, or sit down at the machine, and compare the color of your ticket to the small LCD screen that is present on the machine.
    1. Important: If the colors don't match, alert the poll worker.
  5. When you are ready to vote, press the black arrow next to each choice.
    1. Note: If you make an incorrect selection, press the black arrow a second time to deselect that option. Then press the black arrow next to the option you prefer.
  6. When you have finished voting, press the Cast Vote button.
    1. Important: Do not push the Cast Vote button until you are completely finished. Pushing this button finalizes the process, and you cannot undo it.

    Different push-button DRE machines use slightly different procedures. Some require the machine to be set up by a poll worker, and others don't. If you are unsure of what to do when you check in at your polling place, don't be afraid to ask a poll worker.

    Note: Some push-button DRE machines use digital displays in addition to physical buttons, in which case you may need to push Next Page several times to see all of the candidates and measures that you can vote on in that election.

    Examples of push-button DRE voting machines:

    • Microvote Infinity – Some areas of Indiana and Tennessee.
    • Sequoia AVC Advantage – Statewide in Louisiana, and some areas of New Jersey, Pennsylvania, and Virginia.
    • Microvote MV464 – No longer in use.

    How Dial Electronic Voting Systems Work

    Dial-based electronic voting machines typically use an LCD screen to display the ballot, but they don't use touchscreens. Instead of tapping on the screen to make your choices, you have to rotate a dial to make selections.

    The dials on these DRE machines work in a similar manner to old iPod click wheels. Rotating the dial in one direction causes the selection on the screen to move up, and rotating it in the other direction causes it to move down.

    Volunteers at your polling place will be able to instruct you on exactly how to place your votes, but here are the basic steps you need to follow to vote using a Hart Intercivic eSlate:

    1. Upon arrival at your polling place, a poll worker will verify your voting status and provide you with a code.
    2. Approach an available eSlate, as directed by poll workers, and familiarize yourself with the on-screen instructions.
    3. Choose whether to navigate the device with the dial or an alternate method.
      1. Note: The eSlate is equipped with large buttons that you can use instead of the dial, or you can connect your own accessibility aid, such as a sip/puff device via a 3.5mm jack. If you require help, seek out a poll worker.
    4. Enter the access code that the poll worker provided you with. If you enter the code correctly, the eSlate will present you with the first page of your ballot.
    5. Use the dial to select the candidates and measures that you wish to vote for.
    6. If you choose to avoid voting in some races, you will need to press the Cast Ballot button when you are ready to finish.

    Note: In some cases, the eSlate will be equipped with a voter-verifiable paper trail. If your voting machine is so equipped, it will print a receipt of your ballot choices when you finish. If the receipt is wrong, you will have the option to reject the ballot and try again.

    Examples of dial-operated DRE voting machines:

    • Hart Intercivic eSlate – Statewide in Hawaii, and some areas of California, Colorado, Idaho, Illinois, and Ohio.