Forest wrote (in part, under "Recent postings"):
> My perspective on single winner methods has moved more and
> more towards
> the point of view that ranked ballots are costly in terms of voter
> patience (as opposed to the cost of voting machines, ballot counting,
> etc.), and that the best Condorcet methods just barely
> justify that cost
> in public elections, if at all, and that the other methods
> based on ranked
> ballots fall far short of justifying that cost, though various ranked
> methods including Borda may have other applications in other venues.
These comments about ranked ballots prompt me to share some results from
an in-progress analysis of the ballots from one of the STV-PR elections
for the Irish Dail in 2002. Ireland has used STV-PR to elect both
houses of its Parliament since 1920. In 2002 all-electronic voting was
used in three constituencies (districts) and the full ballot "papers"
have been made available on the web. So far I have looked at only one
of these datasets, for Meath.
There were 14 candidates for 5 places. The two largest parties (FF and
FG) both put up 3 candidates. Four smaller parties each put up 1
candidate, and there were 4 non-party candidates. There were 64,081
valid votes, so we have quite a robust dataset. There is no restriction
of any kind on the number preferences a voter may mark.
The average number of preferences marked was 4.65. Every candidate was
marked as every possible preference (1 - 14) by at least some voters.
The smallest group was 46 voters (0.07% of total) for one of the 14th
preferences. The largest group was 11,534 (18% of total) for one of the
1st preferences.
Number Percentage
of Prefs of
marked Voters
1 5%
2 7%
3 33%
4 19%
5 13%
6 8%
7 4%
8 2%
9 1%
10 1%
11 1%
12 1%
13 1%
14 4%
There was an interesting difference in behaviour between the
'supporters' of the two parties that both put up 3 candidates.
(Supporter defined here as a voter who gave his or her first preference
to any one of that party's 3 candidates.) Significantly more of FF's
supporters stopped at 3 preferences than did FG's supporters. The
balance was made up at 5, 6 and 7 preferences, with a few more at 8, 9
and 10 preferences.
Number
of Prefs
marked FF FG
1 4% 3%
2 6% 5%
3 40% 28%
4 20% 20%
5 12% 16%
6 6% 10%
7 3% 5%
8 2% 3%
9 1% 2%
10 1% 2%
11 1% 1%
12 1% 1%
13 1% 1%
14 3% 4%
Total number of Supporters: FF = 28, 786 FG = 17,452
Between them these two parties gained 72% of the first preferences.
It is interesting to see in detail how real voters behave in real
elections.
Of course, the ballots for all the other STV-PR constituencies were
recorded on paper as usual and sorted and counted by hand, as they have
been at every election since 1920!
James
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