What are the actual mechanics of counting rank-choice (instant-runoff) votes?

Question

I've been volunteering at my City Clerk's office as a poll worker working on preparing to count votes on vote-by-mail and early-voting ballots.

Our work is governed by very specific procedures (as it should be). How will all that change with Ranked-Choice balloting?

An example of a procedure: the airgapped scanning computer in each ballot box, when polls close, prints three copies of a cash-register-tape type report showing candidate/votes, &c. The polling place warden places one copy of the tape in a envelope, seals it, and hands it to a pair of other workers to deliver to City Hall accompanied by a police officer. The warden posts the second tape for public view, and puts the third one in a lockbox for secure archival.

This is Massachusetts USA. We use fill-in-the-oval paper ballots. Each ballot box has a scanner computer that counts the votes by scanning the darkened ovals. Those scanner machines print the register tapes. The scanner computers are airgapped, and not connected to any network. (We save the paper ballots in case there are questions or a recount, but otherwise we trust the scanners. It's a system with high integrity.)

Then somebody at City Hall writes the results on a whiteboard for all to see, and tells the state.

My question: when we have to start handling Ranked-Choice / Instant-Runoff style ballots, how will the register tape reports, and their roll-up, change? What information must be on each register tape? Will it be harder to transcribe and audit accurately?

How did they do it, practically speaking, in the state of Maine in 2018?

How are we going to actually do this? How hard will it be to train ourselves to do it right? Any experience and wisdom out there?

Edit In the comments, somebody told me to ask the City Clerk for instructions. He's right. We don't want our poll workers taking instructions from randos on the 'toobz. My question is more about "how does it work?" than "what are the steps to follow?"

Answer 1

Matt Dunlap, the Secretary of State in the State of Maine, USA, gave a presentation about how they handled ranked-choice voting. https://youtu.be/K2SsQ6CiLKc He declared it a success, saying they didn't have any lawsuits or disputes about the results.

Some takeaways:

• They designed the ranked-choice ballot and then drove around the state giving presentations and soliciting feedback. People liked the design.
• They standardized state-wide on a single vendor for the scanner computers used in their cities and towns.
• In the first round, they counted all first-choice votes as if they were traditional plurality votes and used the traditional reporting systems. Races where the first-choice candidate received a majority of votes where decided that way, and results were posted. Only races where the first-choice candidate received no majority were handled by ranked-choice techniques.
• The state hired a bonded-courier company to carry materials from the cities and towns to the state's tabulating room in the capital Augusta, and then to return them to the cities and towns for archival.
• They rented an expensive high-speed ballot scanning machine to deal with the ballots that had been hand-counted by local election officials (many small towns in Maine don't have their own scanner computers, but rather count the mark-sense ballots by hand).
• They somehow gathered the scanned-ballot data from the towns with scanner computers. One of Mr. Dunlap's slides mentioned the couriers carrying electronic media, but there was no elaboration of that.
• They used software furnished by the scanner vendor to run the ranked-choice algorithm.
• They had to design a special process on-the-fly (in their first RCV election) to enter the votes from unscannable or damaged ballots.
• They didn't have anything resembling a successful write-in campaign, so write-in votes were not a factor for them in the election Mr. Dunlap described. Mr. Dunlap actually mentioned "Daffy Duck" as a written-in name.

It's reassuring to hear his description.

If the voters approve RCV here in Massachusetts in our upcoming election, a couple of things come to mind for our process.

1. It would be good for the election law to change so local officials may create replacement ballots for damaged or otherwise unscannable early-voting ballots. (It's not a factor for in-person voting because the scanner kicks the ballot back to the voter in those cases for correction.)
2. Our plurality vote-counts come out of each scanner on paper register tapes. But for RCV the central tabulation facility will need all possible permutations of candidates / blanks. Maybe the scanners should print QR codes along with readable text? Maybe the results should be written onto a CF card?