[EM] Condorcet and other authors on Condorcet (and how does range voting fit in?)

[Abd ul-Rahman Lomax]

At 04:36 PM 5/17/2010, robert bristow-johnson wrote:
>i am curious how Range can be directly compared to Condorcet, IRV, or
>anything that uses a Ranked Ballot.  the ballots are different.
>assumptions need to be made in order to compare them.

It's pretty straightforward: Range ballots show preferences, in 
general. You can derive a preferential ballot from any range ballot, 
as long as the preferential method allows equal ranking. And from a 
collection of Range ballots, you could even assemble a collection of 
preferential ballots that are equivalent as a set.

I've often said that Range voting is like having N votes to cast in 
an Approval election. In this case, to translate the Range ballot to 
a non-equal ranking ballot, you would divide up the votes from the 
equal ranking so that half of them voted one direction and half the 
other, thus providing in the overall preferences, equal social 
preference order. (Okay, so you might have to use fractional votes, 
but surely that wouldn't be too much to consider!

Note that all methods except those that require full ranking (as in 
Australia) do allow equal ranking at the bottom. I find it bizarre 
that it was ever considered a problem to allow equal ranking at other 
than the bottom.

To compare in the other direction, one treats a ranked ballot as a 
Range ballot, making the assumption that all expressed preferences 
have equal strength between them. In some cases, it might be 
appropriate to distribute these preferences over the range of 50-100% 
instead of over the full range, or some other range. A truncation 
ballot does express a preference for all ranked candidates over all 
unranked candidates, so an explicitly ranked candidate should not be 
ranked at the lowest possible rank.... Unless write-in votes are not 
allowed and a ballot does rank each and every candidate.