Advantages of STV
The advantages claimed for PR generally apply to STV systems. In addition, as a mechanism for choosing representatives, STV is perhaps the most sophisticated of all electoral systems, allowing for choice between parties and between candidates within parties. The final results retain a fair degree of proportionality, and the fact that in most actual examples of STV the multi-member districts are relatively small means that a geographical link between voter and representative is retained. Furthermore, voters can influence the composition of post-election coalitions, as has been the case in the Republic of Ireland, and the system provides incentives for interparty accommodation through the reciprocal exchange of preferences between parties.
STV also provides a better chance for the election of popular independent candidates than List PR, because voters are choosing between candidates rather than between parties (although a party-list option can be added to an STV election; this is done for the Australian Senate).
Disadvantages of STV
The disadvantages claimed for PR generally also apply to STV systems. In addition:
- STV is sometimes criticized on the grounds that preference voting is unfamiliar in many societies, and demands, at the very least, a degree of literacy and numeracy.
- The intricacies of an STV count are quite complex. This has been cited as one of the reasons why Estonia decided to abandon the system after its first election. STV requires continual recalculations of surplus transfer values and the like. Because of this, votes under STV need to be counted at counting centres instead of directly at the polling place. Where election integrity is a salient issue, counting in the actual polling places may be necessary to ensure legitimacy of the vote, and there will be a need to choose the electoral system accordingly.
- STV, unlike Closed List PR, can at times produce pressures for political parties to fragment internally because members of the same party are effectively competing against each other, as well as against the opposition, for votes. This could serve to promote ‘clientelistic’ politics where politicians offer electoral bribes to groups of defined voters.
- STV can lead to a party with a plurality of votes nonetheless winning fewer seats than its rivals. Malta amended its system in the mid-1980s by providing for some extra compensatory seats to be awarded to a party in the event of this happening. Many of these criticisms have, however, proved to be little trouble in practice. STV elections in the Republic of Ireland and Malta have tended to produce relatively stable, legitimate governments comprising one or two main parties.
Australian Senate - Queensland (2007)
Each vote is not counted equally and the method of segmentation and the way in which the Surplus Transfer Value is counted distorts the proportionality and outcome of the election.
By way of example if you exclude all candidates in the 2007 Queensland senate election except the last seven candidates remaining )3 Liberal/NP; 3 Labor Party and 1 Green) in the counts and redistribute the vote as though the other candidates had not stood the Australian Green's Candidate, Larisa Waters, should have been elected instead of the Australian Labor Party third candidate.
This anomaly arose as a direct result of the method of segmentation used in counting the Australian Senate vote.
Analysis has demonstrated that using the Meek method and the Wright System the results of the election would more accurately reflected the voters intentions then the current system in use.
The current system of segmentation was designed to facilitate a manual counting process, sacrificing accuracy for a speedy count. With the use of computer aided counting the application of Meek or the Wright System is preferable. the Wright System is a linear exhaustive reiterative preferential counting method.
One transaction per candidate. if the number of vacant position is not filled then the candidate(s) with the lowest votes are excluded and the count is reset and started from scratch. All votes are distributed as a singe transaction proportionally to their original value without segmentation or distortion in the count. The estimated time in counting the Australian Senate election using computerized voting data varies between 1 to 3 hours.
More information.
Meek: http://en.wikipedia.org/[…]/Meek%27s_method#Meek.27s_method
Wright: http://en.wikipedia.org/wiki/Wright_system