Today, most RCV elections are conducted using optical scan voting systems. The latest machines from the largest vendors (ES&S, Dominion and Hart Intercivic) include options to allow jurisdictions to administer RCV elections.
Following is a short summary of options for administering RCV elections. You can also download the full vote counting options memo as a pdf file here.
Using Major Manufacturer Voting Systems Configured for RCV
Under this option, the voting system itself both reads and internally tabulates RCV ballots. Provided ballots can be easily centralized, for example in a small jurisdiction or in an election conducted entirely by mail, this may be the easiest and least expensive option.
Two manufacturers have voting systems currently certified by the Election Assistance Commission to conduct RCV elections: Hart Intercivic and Unisyn. Dominion has also reported that it is willing to modify its current system for RCV readiness.
This method is used by cities in the California Bay Area with Dominion voting systems, and will be used in Saint Paul (MN) in 2017 with a Hart Intercivic voting system.
Export Ballot Data and Tabulate Using Commercial, Off-The-Shelf or Third Party Software
Many jurisdictions now use digital scanning machines that can capture the image of each ballot and export data from that process into a format that can be read by a commercial, off-the-shelf software spreadsheet such as Excel or private vendor software.
This approach has been adopted as the default way of conducting RCV elections using the latest systems from ES&S. Any ES&S system using the DS-200 tabulators can be modified to convert ballot data into a common spreadsheet format and export it onto a portable USB drive, and ES&S systems beginning with EVS 188.8.131.52 have this capability built into the system.
This method is used by Minneapolis (MN) and Portland (ME).
Centralizing Ballots or Ballot Data Following a Precinct-by-Precinct Count
If counting is typically performed on a precinct-by-precinct basis, the simplest option for administering an RCV election is to use existing precinct machines to count first choice tallies; then, in the event that this precinct count does not determine the outcome of all RCV races, collect ballots or ballot data in a central location and then centrally tabulate the round-by-round results.
This method was used in North Carolina and is the method planned for use in Maine beginning in 2018, if Maine's ballot initiative for RCV passes in 2016.
Work with a Private Vendor
Jurisdictions able to incorporate the use of voting systems that do not have federal and/or state certification can work with an independent vendor in a central count. Such a jurisdiction would run its elections just as usual, with a sensible ranked choice voting ballot design, and count first choices as usual on its current machines. If the outcome were not determined by the first choice count, ballots would then be collected centrally, where the independent vendor would use its system to scan the ballots and generate the RCV results.
This method was used in Portland (ME) in 2011 and by Takoma Park (MD) in 2007, both with the private vendor TrueBallot, who also conducts RCV tabulations in Cambridge (MA).