Candidates are elected or eliminated in a series of ballot counts beginning the morning after the election and lasting about 5 and one-half business days.
The Method
The method of voters ranking candidates in a single election and the method of counting the ballots is called "proportional representation." "Preference voting" is more descriptive of what voters do.
With proportional representation, you vote for as many candidates as you like. The decision is not whom to vote for, but how to rank the candidates: 1st choice, 2nd choice, 3rd choice, and so on.
A pencil, a paper ballot and a long list of names to rank
When you go to the polls, you're handed two long paper ballots, three if there are any ballot questions. Pencil a "1" in the box to the left of candidate you like best, a "2" next to your 2nd choice, and so on until you've exhausted the list of candidates your willing to support or there are no names left to rank.
If the candidate you rank #1 on your paper ballot doesn't receive enough votes to get elected, your ballot will be reassigned to the candidate you marked #2 if he or she is still in the running when your ballot is transferred. If your #2 has already been "elected" or "defeated" in the count, your ballot moves to your #3 choice and so on down the line till your ballot elects a candidate or your preferences are exhausted.
How many votes does it take to win?
The number varies but the percentage is fixed based on the number of seats being contested. For City Council 1/10 of the valid ballots cast is the magic number. For School Committee the number is 1/7. The divisor is one more than the number of seats contested.
In 1993 the magic number (the "quota") was 3001 votes to get elected to School Committee and 2182 votes to get elected to City Council.
If a Council candidate gets more than 10% of the total valid #1 votes at the end of the first official counting of the ballots, that person is declared "elected". In 1993 only Ken Reeves made quota on the first count for Council. Henrietta Davis and David Maher made quota (just over 14%) on the first count of the School Committee ballots.
Each count is like a new primary election
In the second count, the "surplus" ballots of the winner with the most #1 votes are reassigned to the candidates listed #2 on those surplus ballots. If other candidates also make quota on the first count, their surplus votes are transferred in the subsequent counts.
After the 1st choice surplus votes are redistributed, any candidate who has less than 50 votes , is declared "defeated." Votes from these "defeated" candidates are reassigned in the next count.
At each count the "contending candidate" with the lowest number of #1 and redistributed votes is declared a defeated candidate. Each ballot from the defeated candidate's pile is reassigned to the next highest ranked candidate who is still in the running.
When redistributed votes bring a contending candidate to "quota" that candidate is declared "elected" and no additional ballots are assigned the elected candidate.
PR in action
From one count to the next, the ranking of contending candidates may change. In the 1993 School Committee Race, 6th place winner Robin Harris placed 7th in #1 votes (44 votes behind Henry Lukas). But when the 876 surplus votes of 1st place winner, Henrietta Davis, were redistributed Harris picked up 364 #2 votes putting her ahead of Lukas by 28 votes. By the 5th count 5 candidates were elected, one was defeated, and Harris' lead over Lukas had narrowed to 6 votes.
By the 8th count only Lukas and Harris remained in contention for the sixth seat on the Committee. Harris' picked up 190 transfer votes from Sal Framondi giving her a 45 vote lead over Lukas. On the 9th count Lukas's 2432 ballots were redistributed. At least 524 of Lukas' voters had ranked Harris on their ballots bringing her total #1 plus transfer votes to 3001 and electing Harris to the last seat on the Committee. Harris victory over Lukas came in large part from supporters of Henrietta Davis and Christine Aruda who ranked Harris higher than Lukas. ( A 72 vote edge from Davis ballots and 54 vote edge from Aruda ballots.)
The easiest way to understand how PR works if you've made the link yet is to look at the actual ballot counts in the 1993 School Committee Race.
For more information on Proportional Representation and Cambridge's form of government and where to vote, visit Cambridge Government Election Department.
A National Conference on PR is coming to Boston and Cambridge Nov.11-12.