The Single-Transferable-Vote System

The following description has been adapted by Suzanne Kemmer and David Tuggy from the relevant portions of Parliamentary Procedure at a Glance by O. Garfield Jones (1971, Hawthorne), pp. XXXIV-XXXVII.

Two parliamentary voting systems

The Single-Transferable-Vote System is one of the two principal methods of choosing officers by majority vote found in parliamentary systems.

In the traditional method of majority voting, voters are asked to select just one among the candidates for a given office. Runoff vote(s) are required if there is no candidate whose votes constitute a majority of the total votes.

The main disadvantages of the traditional system are that candidates who have significant percentages of positive votes can be eliminated in the first round; and there is often a need for more than one round of voting, which can take up a good deal of parliamentary meeting time.

The principal alternative to the traditional method has been gaining popularity in many governmental and non-governmental organizations run by parliamentary rules.

It is called the Single-Transferable-Vote system (STV system). The name derives from the fact that each voter has a single vote, but this vote “transfers” from higher to lower ranked choices by the same voter in successive vote counts.

In this system, a voter’s indication on a ballot that a candidate is not his or her first choice among the candidates is not a vote against that candidate, as it would be in the traditional parliamentary voting method. Instead, the vote can be applied to such a lower-ranked candidate if the voter’s higher-ranked choices fall out of the running first.

This system does away with multiple rounds of balloting, as in effect it condenses multiple, conditional choices into one ballot. Each person has one vote, but this vote potentially passes down the voter’s ranked candidate list until it reaches a candidate who has enough votes to stay in the running until the final count yields a majority. Thus, no vote is “lost”, even if a voter’s earlier choices are less popular candidates and eliminated in early rounds of counting.

Voting procedure in the STV system

The Single-Transferable-Vote system operates as follows. The voters are asked to rank the candidates from the candidate pool. For example, if there are six candidates for an office, each voter ranks them as choices 1, 2, 3, 4, 5 and 6.

A voter may also choose to leave one or more candidates unranked; and may also choose to vote “NO” for one or more candidates. The significance of unranked candidates and of “NO” votes will be discussed in more detail in the following section.

Those designated to count the votes are called tellers. The tellers first place all the first-choice votes in piles, one pile for each number one candidate. They then count these first-choice piles, and if it is found that one candidate has a majority of the total votes cast, that candidate wins the election.

However, if no candidate gets a majority of the total number of ballots, then the candidate having the smallest first-choice vote is declared “out of the race” or eliminated. That candidate’s ballots are all redistributed by the tellers to the second choice candidates on the ballots, by placing the ballots on the vote piles of the remaining uneliminated candidates. ^[1]

Any ballot with neither any remaining ranked names nor any “NO” votes for candidates still in the running is termed an exhausted ballot. Once exhausted, a ballot is eliminated from the election by subtracting it from the total number of votes cast. The number of votes required for a majority is thus adjusted downward by the number of exhausted ballots. The following section will discuss exhausted ballots in more detail.

If any candidate now has a majority, that candidate is the winner. But if the addition of these second-choice ballots still does not give any candidate a majority of the total number of (non-exhausted) ballots, then the candidate with the lowest total on the second count is declared out of the race (eliminated), and his or her ballots are redistributed according to the next choice, among remaining candidates, on each ballot. All of the piles of ballots for the candidates still in the running are then recounted.

This system of dropping off the candidate with the lowest number of votes continues until one candidate gets a majority of the total vote (minus the exhausted ballots as described above).^[2] Usually under this system, one candidate will eventually secure the required majority.^[3]

“NO” votes and unranked candidates

The system allows voters to indicate a vote of “NO” for a particular candidate they do not want to see elected. If a voter selects “NO” for a given candidate, their vote will never transfer to that candidate in any round of voting, but they will still have voted: as long as that candidate is in the running their “NO” vote will be included in the number of total votes, thus affecting the number of votes necessary for a majority. A large number of “NO” votes for a candidate who nevertheless makes it to the final round of counting will make it hard for that candidate to obtain a majority of the vote. The higher the total vote, the more votes are needed for a majority, but “NO” votes can by definition never count towards a majority for the candidate they apply to. Thus “NO” votes actually count against a candidate.

Another way the voter can ensure that his or her vote will never transfer to a given candidate is by leaving that candidate unranked. However, the effect here is different from a “NO” vote. In this case, if no rankings are marked on a ballot for any candidates still in the running in a given round of counting, the ballot becomes exhausted and is eliminated from the total of votes cast. The result is that the number needed for a majority is decreased by such a ballot.

In effect, an exhausted ballot will function as an abstention for an unranked candidate that is still in the running: by not ranking a candidate, the voter is requesting that the ballot not be counted FOR the unranked candidate (should that candidate still be in the race in a round of counting), nor should it be counted AGAINST the candidate as would a “NO” vote. A ballot is simply not applied in any count or total, once it has no further candidates on it that the voter has ranked positively OR voted against. In other words, an exhausted ballot expresses that there are no further candidates for whom the voter has a preference for or against, among the remaining candidates in the election.

Ballot counting time

Because there are successive rounds of counting of the same ballots, the counting process takes longer than a single-choice balloting procedure. Still, the entire process almost always takes place with just one ballot, no matter how many candidates there are. This saves the assembly’s time, and arguably the tellers’ time as well. Moreover, the multi-round counting process need not delay the group as a whole, since in principle the group can go on to other business while the counting is taking place.

Filling other positions with the same ballots

It is sometimes the case that a parliamentary body allows itself to choose more than one winner from the same pool of candidates.

For example, it might choose a president first and then a vice president from the same pool of candidates. Or, it can choose more than one candidate for functionally equivalent positions, selecting such candidates as multiple winners from the same larger slate of candidates.

The ICLA, for example, elects three Regular Members for its Governing Board from a more numerous slate of candidates for Regular Member proposed at its Business Meeting.

In such a case, it is reasonable and time-saving to use the same ballot slips for the multiple elections.

To do this, it is necessary only to remove (“strike”) the most recent winner’s name from the ballots, and then repeat the ballot-counting procedure described above with the remaining names on the slate until the desired number of winners is obtained.

Illustration

Footnotes

[1] If there is a tie for last place, at this or any similar stage in the balloting, all candidates in the tie are declared out of the race and their ballots redistributed to the remaining candidates in accordance with the next choices on those ballots.

[2] This procedure includes the case where only two candidates of unequal vote remain and neither has a majority of the total. (There must be some “NO” votes to produce this result.) In this case the one with fewer votes is declared out of the running, and all of this eliminated candidate’s ballots that also list the leading candidate are placed on that candidate’s pile. This final distribution will almost always result in a majority for that remaining candidate.

[3] The only cases that will NOT result in a winner, and will therefore require a runoff vote, are: (a) those in which there is a tie among all remaining candidates, and (b) cases where there are more “NO” votes for the remaining leading candidate than votes of any numbered rank, thus not yielding a majority vote for that final remaining candidate.

Updated 22 Oct 2007

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