Sorting Out the Kinks in Ranked-Choice Voting

Last month Arlington, Virginia, used a relatively complicated variant of ranked-choice voting in its primary to select two Democratic candidates for its county board. But the county will revert to conventional voting for a time at least, Teo Armus and Kyle Swenson report at the Washington Post:
The Arlington County Board declined to move forward Saturday with ranked-choice voting for November’s general election, halting the Northern Virginia suburb’s experiment with the increasingly popular voting system, for now.
Some will probably bill this as a rebuke of ranked choice voting (RCV) in general, but that’s not a fair assessment. Most of the 50 or so American cities and other jurisdictions that use RCV use a straightforward variant, suited to a race that elects a single winner to a single office (say, mayor or councilmember representing a particular district). Candidates with the fewest votes are eliminated in turn and their ballots redistributed to their voters’ next choices until one candidate obtains a majority of the votes that remain. This kind of RCV, commonly called “instant-runoff voting,” allows voters to weigh in immediately in a virtual runoff to resolve races in which no candidate won a majority outright. Instant runoff has the great virtue of simplicity: it’s not only simple to explain how to fill out your ballot, but also simple to explain how the votes are then tabulated.
But ranked choice can also be used for multi-seat races in which the two or three top finishers each win a seat (or advance to a general election from a primary, as in Arlington). These models are more complicated. Even if voters grasp readily how to indicate their preferences on the ballot, the tabulation process is considerably harder to explain to the lay person than with the instant-runoff kind. In the Virginia law prescribing how localities may use ranked-choice voting, the rules for tabulating instant-runoff RCV consist of two sentences. The rules for tabulating multi-winner elections go on for 11 sentences and rely on concepts such as “current transfer value” and “surplus fraction.”