The "Meek" method in pSTV Windows version 0.7 from http://stv.sourceforge.net/ , seems to give counter-intuitive results as shown below.
My initial naive expectation was that the block voters for A, B, C, D candidates should win all four seats since each of them has more first, second, third and fourth preference counts than each of the candidates in the block E, F, G, H at every level. Also I did not expect H to be eliminated since it has more first place preferences than F!
I got trapped into thinking that first preferences should have much more weight in determining the winners in STV. Thus the results looked counter-intuitive. Part of the problem arises from how votes from eliminated candidates get re-allocated and how surplus votes from winning candidates get reallocated
Once a candidate is eliminated or elected, those ballots which had him listed first, have the remaining preferences, after the next one, ignored.
Where I get hung up, is the fact that ALL of the votes of an eliminated candidate gets re-allocated to the next preferred candidate on the list, ignoring any of remaining preferences on that voter's ballot.
The voter who picked a losing candidate as a first preference, loses considerable control of how he wanted to allocate portions of his vote to his remaining preferences. Also, he has NO IDEA BEFOREHAND as to what fractions of his vote will get reallocated to other candidates. As a result, some fractions of his vote may eventually get re-allocated to candidates that were NOT on his list. I think this is where I and the the public gets VERY apprehensive about STV.
To minimize this problem, there should be some rule added to STV, so that the votes of an eliminated candidate is allocated to each of the remaining candidates on his list in a manner inversely proportional to their ranking. So, in the example below, when E gets eliminated, his 1200 votes should be allocated in round two by (1/2)/(1/2+1/3+1/4) = 6/13 to F, 4/13 to G and 3/13 to H. Note: This is different from the ranking of voters for F whose next ones on the list were G, H and E.
In round four when H gets eliminated, the 1250 votes should be allocated to F and G in proportion to 4/7 and 3/7 respectively, instead of all to F.
And so on...
A similar rule could also be made for re-allocating surpluses from elected candidates according to the ALL the preferences remaining on the lists of the ballots.
These similar anomalies also occur in BC-STV and it should be eliminated or minimized in BC-STV.
The question is: Would this additional complexity in allocating votes of eliminated candidates and surpluses of elected candidates more equitably, make the voters and the candidates any happier that the system becomes more(?) proportional by following the voters wishes more closely and is thus more democratic?
Yours democratically, Cheers from sunny Tsawwassen.
Jim Ronback Tsawwassen, BC Canada
PS. In spite of these shortcomings, I'll vote yes for BC-STV on May 17 and hope that Elections BC will make these improvements if and when it gets implemented.
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Ballot input:
1299: A B C D 1276: B C D A 1274: C D A B 1251: D A B C 1200: E F G H 1224: F G H E 1226: G H E F 1250: H E F G
Election: Ballot data from D:\Program Files\pSTV\Block.blt. Method: Meek STV Number of Ballots: 10000 Threshold Name: Droop Dynamic Fractional 8 candidates running for 4 seats.
R| A| B| C| D| E| F| G| H|Exhaus|Surplu|Thresh
--+-------+------+------+------+-------+------+------+-------+-------+------+------
1|1299.0|1276.0|1274.0|1251.0|1200.0|1224.0|1226.0| 1250.0| 0.0| 0.0|2000.0
2|1299.0|1276.0|1274.0|1251.0| |2424.0|1226.0| 1250.0| 0.0| 424.0|2000.0
3|1299.0|1276.0|1274.0|1251.0| |2000.0|1650.0| 1250.0| 0. 0| 0.0|2000.0
4|1299.0|1276.0|1274.0|1251.0| |3031.4|1868.6| | 0.0|1031.4|2000.0
5|1299.0|1276.0|1274.0|1251.0| |2000.0|2900.0| | 0.0| 900.0|2000.0
6|1299.0|1276.0|1274.0|1251.0| |2207.1|2000.0| | 692.9| 484.3|1861.4
7|1299.0|1276.0|1274.0|1251.0| |1888.3|2062.5| | 949.2| 330.5|1810.2
8|1299.0|1276.0|1274.0|1251.0| |1852.5|1849.5| |1198.0| 181.2|1760.4
9|1299.0|1276.0|1274.0|1251.0| |1774.3|1803.5| |1322.2| 106.7|1735.6
10|1299.0|1276.0|1274.0|1251.0| |1745.7|1752.9| |1401.4| 59.2|1719.7
11|1299.0|1276.0|1274.0|1251.0| |1724.5|1731.0| |1444.4| 33.3|1711.1
12|1299.0|1276.0|1274.0|1251.0| |1714.0|1716.9| |1469.1| 18.5|1706.2
13|2550.0|1276.0|1274.0| | |1707.7|1709.5| |1482.8| 856.9|1703.4
14|1703.4|2122.6|1274.0| | |1704.3|1705.2| |1490.5| 427.9|1701.9
Round 1: Count of first place rankings.
Round 2: Eliminating candidate E.
Candidate F is elected.
Round 3: Transferring surplus votes.
Round 4: Eliminating candidate H.
Round 5: Transferring surplus votes.
Candidate G is elected.
Round 6: Transferring surplus votes.
Round 7: Transferring surplus votes.
Round 8: Transferring surplus votes.
Round 9: Transferring surplus votes.
Round 10: Transferring surplus votes.
Round 11: Transferring surplus votes.
Round 12: Transferring surplus votes.
Round 13: Transferring surplus votes.
Eliminating candidate D.
Candidate A is elected.
Round 14: Transferring surplus votes.
Candidate B is elected.Winners are A, B, F, G.
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