With three special legislative elections coming up, including in the 3rd Berkshire District, groups advocating "good government" made a pitch this week for "instant runoff voting" in state elections.

A coalition of election reform advocates and state lawmakers announced Wednesday that they are filing a bill to establish instant runoff voting in all special elections, though the system is unlikely to be changed before the March 15 primary.

Under an instant runoff system, voters are allowed to vote for multiple candidates under a ranking system, which supporters said ensures that the winner of the election receives a majority of the vote.

Pamela Wilmot, executive director of Common Cause Massachusetts, said instant runoff voting would particularly help special elections, where voter turnout is low but there are usually many candidates.

"This allows voters to choose candidates with their hearts as well as their minds," Wilmot said.

Wilmot gave the example of a primary in which three candidates are running. Two of the candidates may appeal to a constituency that represents a majority of that district, but because they split their shared base, the candidate who is "different" ends up with a plurality of the vote.

"It's not democratic," Wilmot said.

She used the 2000 presidential election as an example, when Green Party candidate Ralph Nader took 2 percent of the vote, possibly enough to tip the election in the favor of George W. Bush over Al Gore.

In an instant runoff system, voters are allowed to rank the candidates in the order of their preference. However, if they wish, they may only vote for one candidate.

The candidate who receives a majority of the vote is the winner. However, if no candidate receives more than 50 percent of the vote, the candidate with the fewest votes is eliminated, and those votes are reallocated to those voters' second choices.

That process continues until one candidate receives a majority of the votes.

State Rep. Ellen Story, D-Amherst, one of the sponsors of the bill, acknowledged that the bill "has no chance of passing" in time to change the voting process in the upcoming special legislative elections in Pittsfield and Boston.

The House has not formed committees yet, and it's highly unlikely that a bill related to changing the voting system would be approved in a matter of weeks.

She said the point was to call attention to flaws in the process of picking candidates in a primary. Some contests can have several candidates, and a person who gets just a small fraction of the vote can be the winner.

Advocates noted that instant runoff voting would encourage more third party candidates to run, as well as make it less likely that a third party candidate could be precluded from attending a debate.

Critics of instant runoff voting have said it's confusing to voters and would also be a tallying headache for municipal clerks and election officials.

Last November, a glitch in San Francisco's new municipal election instant runoff system created a delay in the counting of ballots. The software did not tabulate the data as it was supposed to, election officials said.