OXFORD, England – In November’s mayoral election, Portland will use ranked choice voting (RCV) for the first time.

This electoral process appears to be an improvement on the old method, enhancing the likelihood of selecting a candidate who is minimally acceptable to a majority of residents, rather than the candidate who is most acceptable to a plurality.

The downside is that RCV is far more complicated in terms of rules and strategies, especially in a race with 15 candidates.

To prevent the election from getting mired in misunderstanding and misadventure, we try to spell out what appear to be its most salient features and some of the more obvious strategies.

The key variable in the balloting process is the “break,” or the count that decides the election.

If one candidate obtains a majority in the first count, the break is one.

If it takes five counts — so that all votes up to the fifth preference are tallied — then the break is five.

Further, the break divides the candidates into the “head” — those candidates who survived until the break — and the “tail,” those who are eliminated before the break. Only the votes given to candidates in the head ultimately matter.

Votes given to the tail disappear by the time the runoff process has worked itself out. Finally, the break is important because it determines how important depth of support is to the outcome — it doesn’t matter how many sixth-rank votes you have if the break is at five.

The most obvious, and most disconcerting, difference between the old process and the new is how RCV lends itself to tactical voting, where voters deliberately limit their range of preferences to advance a favorite candidate or candidates.

Suppose a resident votes just for her first and second choices, leaving the rest of the ballot blank. That means the voter is actively withholding support for all other candidates, and this makes her vote more valuable than someone who votes for five, 10 or all 15 candidates.

Once we know about the concept of the break and tactical voting, a few natural strategies appear to emerge, provided there is no single candidate who is able to take an outright majority.

For a front-runner, the obvious approach is to try to be high on everyone’s ballot.

This candidate may not have the most first ranks or second ranks, but by the fifth or sixth count, enough additional votes trickle in to secure a majority.

For a non-front-runner (who can’t employ a strategic-depth approach but still has enough core support to likely end up in the head), coalition-building may be the best bet.

In a coalition, each candidate encourages core constituents to support the candidacy of other designated candidates (a “slate”) and rank them highly.

If that is the case and constituent residents consistently vote just for the slate, the coalition as a whole is guaranteed to win.

Another conceivably powerful strategy could be named “Eight for Haadoow,” after the candidate Hamza Haadoow.

Haadoow likely has enough support among the Somali community to be in the head if the break is fairly high (say, seven or eight). Lacking broad exposure to the city at large, he could succeed by relying on his home constituency to allow him to survive the early rounds and by trying to garner large amounts of weak support by trying to get other voters, who might only be slightly familiar with him but otherwise positively disposed, to rank him as No. 8.

This kind of strategy could also favor someone like Chris Vail, the Portland firefighter and Peaks Island native, who can draw from these two small-but-significant constituencies.

Here we’ve outlined some of the strategies that candidates and voters might try in their campaigns and balloting, but we can’t pretend that this is an exhaustive list.

Our hope is that candidates and voters, when employing their strategies, will remember the goal of RCV: electing a mayor who best represents the city.

– Special to The Press Herald