Note: I wrote this in 2007. Ten years later, it remains generally valid for most election systems.
The diagram below is a simplification of how a county records and tabulates votes. Exact procedures will vary from county to county, and from voting system to voting system. However, the diagram serves as a starting point to understand what happens during a typical election.
The green boxes show what takes place in the polling places. The blue boxes show events at county offices. Red shows electronic connections that may be hackable. Purple shows components of the paper trail. A more detailed explanation follows the diagram.
Voting Procedures Diagram
The diagram above illustrates the following steps.
(1) County or company employees use the central tabulator (yellow) to prepare ballot definition files for each precinct, and place them on memory cards (or packs). These files contain information about what candidates, races, and initiatives should appear on the ballot for each precinct. There is no independent inspection of contents of these files or the cards.
(2) County staff also prepare lists of registered voters for each precinct, to be used when the voters check in. These lists are checked electronically against the Secretary of State’s statewide list in an attempt to verify that the names are valid (see registration).
(3) Voters arrive and check in. Depending on the jurisdiction, they may or may not need to show a photo ID card.
(4) If the registration list shows the voters name, they will be given either
(a) a ballot card, also known as a “smart card”, which contains information on which precinct the voter is in, or
(b) a ballot which they may fill out with some kind of “ballot marking device”, such as a pen, a tablet for the disabled, or even an Automark touchscreen computer.
If there is a registration problem, the voter may demand a provisional ballot which should be checked and counted later.
(5) The voters will then either
(a) insert their ballot card into the touchscreen machine, and register their choices, or
(b) insert their filled out ballot into the optical scanner to be counted.
(6) At the end of the day, poll workers remove the memory cards from the machines, and take them back to the county for tabulation. In some jurisdictions, the poll workers also print out precinct result tapes from each machine. They take these tapes back to the county offices as a partial check on the computerized system.
(7) As the memory cards come in, county or company employees insert the cards into card readers directly connected to the central tabulator. This computer receives and secretly totals the results. There is for all practical purposes, no independent inspection of contents of the cards, nor of the software running the tabulator.
Periodically on election night, the county sends the its results by “secure” electronic means from the tabulator to the Secretary of State’s office, which then announces the statewide totals to the media.
(8) Before, during and after election day, county officials collect, verify absentee and provisional ballots, and insert them into high-speed central optical ballot scanners for counting. They then transfer the totals from the scanners to the central tabulator using the memory cards.
(9) In the days and weeks following the elections, officials (re)count the votes on some of the ballots, and, depending on the jurisdiction, the VVPATS (Voter Verified Paper Audit Trails) from the touchscreen voting machines to see if the totals fit with those reported by the tabulator. For reasons explained under auditing, this important procedure is usually inadequate to ensure fair and accurate elections.
(10) Several weeks after the election, the county reports the final, “certified” results to the Secretary of State’s’ office.