[EM] General PR question (from Andy Jennings in 2011)

Toby Pereira tdp201b at yahoo.co.uk
Fri Oct 3 15:54:32 PDT 2014

When I do ranked votes I normally put greater than signs in, so A>B>C. Also, with approval voting, I'd normally specify above the vote table that it's approval voting, although sometimes it doesn't happen. But I suppose I neglected to do so, because it had followed on from previous examples, which were all approval cases. In any case, I'll try to be explicit in future.
On approval v rank for proportional voting, there's always the problem with ranked voting that you don't know the strength of the preference. With single-winner Condorcet methods, there's the argument that it doesn't matter because every candidate is compared in a head-to-head manner so degrees don't matter. But with multiple-winner methods, it becomes more important. Which would you rather - your single first choice, or your second and third together? You can't say. Also with STV methods, your unused preferences are ignored anyway, so you might have got lucky and got your next choices elected or you might not. But the voting system doesn't take it into account at all. With approval voting, you at least get to say which candidates you like. And if you prefer more information, score voting would be preferable to ranks. It's worth looking at this example from Warren Smith http://rangevoting.org/PRcond.html
It's also worth looking at this slightly more complex example with six to elect. Some voters have bullet voted, some have ranked several candidates.
3: A>B>C>D>E>F
 3: A>C>D>E>F>B
 3: A>D>E>F>B>C
 3: A>E>F>B>C>D
 3: A>F>B>C>D>E
 12: B
 12: C
 12: D
 12: E
 12: F
 14: G
 14: H
 14: I
 14: J
 14: K
 14: L
I'm not sure what your method would do, but STV methods would tend to elect A and five of G to L - e.g. AGHIJK. But it could be that the A voters, while they prefer A, actually wouldn't mind that much about which of their ranked candidates get elected - they might all be from the same party. If they knew what would happen, they could forget A, and this would be enough to get all of BCDEF elected - five candidates instead of just one. This is a case where approval voting would outperform ranked ballots. Yes, it's a contrived example, but it's contrived to show how these voters could go from having just one candidate to having five elected. It wouldn't need to be anywhere near as contrived to make a one or two candidate difference. And when several candidates are being elected, it is less about my single favourite candidate but about the candidates I wanted elected, so it makes sense to reflect that in the type of ballot used.
      From: Richard Fobes <ElectionMethods at VoteFair.org>
 To: "election-methods at electorama.com" <election-methods at electorama.com> 
 Sent: Friday, 3 October 2014, 20:57
 Subject: Re: [EM] General PR question (from Andy Jennings in 2011)
On 10/3/2014 4:26 AM, Toby Pereira wrote:
> Richard, there may have been come confusion because my examples have
> been assuming an approval ballot, so A, C and C, A are the same.
> Obviously if these are ranked ballots this changes things.

Thank you for clarifying.

Can we avoid this ambiguity for the future?

One possibility is to use an "&" (ampersand) between two choices that 
are ranked at the same preference level.  For example, approval ballots 
would look like this:

10 voters: A & B
10 voters: A & C

When ranked ballots are used, there can be a mixture of same-level and 
different-level preferences:

10 voters: A, C & B
10 voters: C & A, B

Another possibility is to omit any symbol between same-level choices:

10 voters: A  B
10 voters: A  C


10 voters: A, C B
10 voters: C A, B

Obviously I'm used to a comma indicating a change in preference level. 
Am I the only person who interprets ballots this way?

BTW, in my opinion a voting method that does not allow a voter to rank 
two choices at the same preference level is not a good voting method.

 > ...
 > I also tend to think that the argument for score or approval ballots
 > gets stronger for proportional representation than for single-winners.

I suppose that by limiting the preferences that voters can express, an 
approval approach might appear to achieve better proportionality.

Yet I think that if full voter-preference information is suppressed, we 
are doing what single-mark ballots now do: hide the unfairness by not 
collecting all the relevant information.

Richard Fobes

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