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Voting matters - for the technical issues of STV

Issue 19, November 2004

(Complete issue in PDF, 135Kb.)


  Report by Steve Todd

On 9 October this year, New Zealand held a number of STV elections using the Meek counting rules. Several problems arose which delayed the final declaration of the results. It appears that the main problem concerned reconciling the number of voting papers that were scanned into the database with the number that were subsequently sent to the STV calculator.
The realisation that discrepancies were occurring led the local councils and district health boards (DHBs) affected, to call in the Auditor-General's office to audit the entire process. While the computer error was discovered and fixed within a few days, the auditing process meant that it took four weeks to complete all the vote-counting. In contrast, the program which actually performed the count, i.e. the STV calculator, appeared to operate without mishap.
A lesser, but equally frustrating, problem was that the ICR technology used to process the ballot papers was unable to read (with a high level of confidence) a considerably higher percentage of the scanned documents than was expected. This led to much more human intervention than was expected, with a consequent increase in the time taken to process the votes.
The Justice and Electoral select committee of New Zealand's parliament intend to conduct an inquiry into what went wrong. A focus of the inquiry will likely be on why the two Auckland-based companies contracted to process the STV votes in the northern part of the country, did so seemingly without a hitch, and in a timely manner, while the Christchurch and Wellington companies contracted to conduct the remaining STV elections (in respect of 7 of 10 councils and 18 of 21 DHBs) did not.
There has not yet been a full explanation of the problems encountered, but there is a suggestion that the computer systems used by the Christchurch and Wellington companies may not have been completely compatible.
There were also widespread claims of voter confusion (said to have been caused by having FPTP and STV elections on the same A3-size voting documents), leading to many Informal (Invalid) votes (errors) and blank votes (non-participation) being cast, that the select committee will no doubt inquire into.
Informal votes in council areas using STV appear to have been no more than usual - 1.08% in Wellington and 1.49% in Dunedin, for example. However, in the remaining 64 council areas, that used FPTP, the Informal rate in respect of their DHB elections was up as high as 10 to 12%.
A likely explanation for this will be poor voting-document design. There was no bold distinction between FPTP and "tick-voting" for the mayoral and council ward elections, and STV and voting by numbering the candidates in the DHB elections. In fact, apparently due to printing restrictions, the DHB elections were set out under the name of the city or district councils they were associated with! This means that some voters (who did not read the voting instructions carefully) carried on tick-voting into the DHB election - more than one tick for the candidates and the vote was informal.
On the brighter side, the actual ballot data is likely to be made available in respect of most, perhaps all, STV elections and hence it will be possible to `check' the counts by re-running them.

  Voting matters

There are 3 papers in this issue:
Readers are reminded that views expressed in Voting matters by contributors do not necessarily reflect those of the McDougall Trust or its trustees.

Papers with citations

  1. B. A. Wichmann: Tie Breaking in STV. (p1-5, PDF 40Kb)
  2. J. Green-Armytage: Cardinal-weighted pairwise comparison. (p6-13, PDF 70Kb) [27, 1-21, PDF].
  3. B. A. Wichmann: A Working Paper on Full Disclosure. (p14-16, PDF 32Kb)

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