In the ever-democratic Cambridge, a group of residents can be highly influential in municipal elections, thanks to its decades-old Plan E form of government.

Under Plan E, the city's most powerful official is the city manager. The City Council sets policy and makes laws which are carried out by the city manager. The mayor serves as chair of both the School Committee and City Council and is chosen by the council, not the voters.

Cambridge has used Proportional Representation (PR) as its voting system since 1941. PR "ensures minority representation with majority control," according to the Cambridge Election Commission's Web site.

When voters go to the polls, they number their choices for candidates in order of preference. To be elected, candidates must reach "quota"--10 percent of the total votes cast plus one vote.

After the first count, those candidates who have met the quota are elected, and their "surplus" votes are randomly distributed to the number two choices on those ballots. Thus, number one votes are critical.

Those candidates who receive less than 50 votes are eliminated and their votes are redistributed. After each succeeding round of tabulation, the candidate at the bottom is eliminated and his votes are redistributed until all nine councillors have been elected.

--Edward B. Colby