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Voting matters - Issue 10, March 1999

An example of ordering elected candidates

C H E Warren

Colin Rosenstiel has proposed that elected candidates can be ordered by successive elimination. In an unpublished note of the same date (May 1998), Eric Syddique has proposed essentially the same method. However, in Newland & Britton, the method proposed is to take the order of election. The purpose of this paper is to show that these two methods can produce very different results.

Consider the following election of 4 candidates from 7 contenders by 600 voters, for which the voting profile is: 

 50 AC
 70 AD
115 BED
100 CD
115 D
 65 ED
 50 FCD
 35 GBED
Since the quota is 120, we obtain the following result sheet from the ascription of the Newland & Britton principles, avoiding the rounding errors which the practical application of their method as given by them introduces.

Hence the order of election is A, B, C and then D.

With the Rosenstiel/Syddique method of successive elimination, with E, F and G eliminated the votes are: 

120 A
150 B
150 C
180 D
B, C and D are selected and A is placed fourth and eliminated henceforth. The votes are then: 
150 B
200 C
250 D
C, D are selected, and B is placed third and eliminated henceforth. The votes are then: 
 
200 C
400 D
C is now placed second and D first. To summarise, the order is D, C, B and then A.

Hence the two methods produce ordering which is exactly the opposite of each other.

References

  1. C Rosenstiel. Producing a Party List using STV. Voting matters, Issue 9, pp7-8, May 1998.
  2. R A Newland and F S Britton. How to conduct an election by the Single Transferable Vote. ERS 3rd Edition. 1997.
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