Voting for more than just either-or


Traditional voting systems only allow people to make a single choice -- a limitation many voters find frustrating, particularly when there is a crowded field of candidates as there was early in the current presidential nominating cycle.

But it doesn't have to be that way.

Alternative voting systems, which allow people to rank their preferences in order instead of simply picking one, have been known for centuries, but have been devilishly difficult to implement and often result in a very slow tallying of results. One example is the system used in the Iowa caucuses, in which supporters of candidates who fail to reach a certain threshold in the first round can then move on to their second choices, and so on until a clear winner emerges.

A new computer software system developed by MIT researchers promises to make such ranking systems just as easy as traditional voting -- and to give results that leave more people satisfied. The system is about to get its first mass-market trial with the cable music network MTV.

Benjamin Mako Hill, while he was a graduate student in the MIT Media Lab's Computing Culture group, created a system called Selectricity, which has been online as a free service since last fall and is about to unveil an upgraded version with more options. With this software, any user can go to the website (www.selectricity.org) and set up a "Quickvote" in just a few seconds, and users anywhere who have access to the Internet can then cast their votes, providing an instant tally.

There's even an ultra-simple version that works through cellphones using basic text messaging. The system is so simple that hundreds of people have been using it for decisions as simple and immediate as where to go for dinner or when to hold a meeting.

But the system is also sophisticated enough to handle real elections, at least on a small scale. In February, a beta version of the new, improved software was used by a national student organization to elect their first board of directors -- and the way that election turned out was a dramatic confirmation of the value of the new system.

Each of 16 campus chapters of the group Students for Free Culture got an equal vote to select five members of their governing board from among a slate of 13 candidates. But as it turned out, the result would have been very different had they used a traditional voting system.

Hill, now a research fellow at MIT's new Center for Future Civic Media, says "the first place winner in plurality didn't even make it into the top five" using the more sophisticated preferential voting system, in which each chapter was able to rank all of the candidates in order of preference. That candidate, who would have been the winner in an ordinary election, "was ranked first more than any other candidate" -- four first-place votes out of 16 -- but "he was very polarizing and was ranked near-last on most of the other ballots," Hill explains. So in a traditional vote, the vast majority of the voters would have been very unhappy with the outcome.

Instead, with the Selectricity preferential voting system -- which allows the results to be scored using any of a variety of different known mathematical systems for selecting winners -- "the first-place winner using the Schulze/Condorcet (and most of the other methods) had only two first-place votes, but was in the top three or four on almost every ballot," Hill says. "It ended up being a real example of the power of preferential elections," leaving a majority of voters satisfied.

Selectricity users can pick which selection method to use when they set up a ballot, but once votes are cast the website also allows users the option of analyzing the results using several alternative methods, so that the outcomes can be compared.

The five methods currently included are:

A traditional simple plurality method: whoever gets the most first-place votes wins.

The "Approval" method, devised in the 1970s, in which people can vote "for" as many candidates as they like -- one vote per candidate -- to indicate which ones would be acceptable, and then all the votes for each candidate are simply added up and the person with the most votes wins.

The Borda count, first proposed in 1770, which awards weighted numbers to each candidate depending on the ranking voters give them (such as 1 for a first-place vote, 2 for second, etc.) and then these numbers are totaled to determine the winner.

The Condorcet method, devised in 1299 and refined in the 18th century, in which each candidate is compared one at a time with each of the others to see which one was preferred over the other by the most people, and then the one who wins the most of these pairings is the winner.

The Schulze methode, a refinement of Condorcet devised in 1997, which uses a complex mathematical formula to compare each candidate's rankings with each of the others.

MTV, which provided Hill with a $30,000 grant for the project last year as a winner of its mtvU "Digital Incubator" competition, is planning to use Selectricity to allow viewers to vote for their preferences among a selection of music videos to be presented in a new program that will be airing in the next few weeks. Details are still being worked out with the network, Hill says.

To give readers a chance to try out the system for themselves, there is a sample vote online at http://selectricity.org/quickvote/usvoting . Simply drag-and-drop each of the five options into your preferred order, and then click "confim vote" to see an analysis of the votes so far.

A version of this article appeared in MIT Tech Talk on March 12, 2008 (download PDF).


Topics: Media Lab, Voting and elections

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