[EM] OpenSTV 2.1.0 released and new OpaVote features

Kristofer Munsterhjelm km_elmet at lavabit.com
Sat Sep 15 03:02:24 PDT 2012

On 09/15/2012 09:55 AM, Juho Laatu wrote:
> On 15.9.2012, at 6.05, Jeffrey O'Neill wrote:
>> You can also now save Condorcet results in HTML format but still
>> working on the best graphics to visualize Condorcet results.
> One solution is to support minmax(margins). With that method you can
> simply draw a histogram that indicates how many new (first preference)
> votes each candidate would need to win (or tie) with the winner /
> current leader.

That also works with minmax(wv), and similar approaches can work for 
least reversal methods and those that use sums of victories rather than 
minimum/maximum ones. However, those visualization methods are still 
linked to specific voting methods, and thus don't provide a general 
visualization of the pairwise results.

I suppose one could use something similar with Kemeny as well: use 
integer programming to find the pairwise sum of scores for the best 
transitive ordering that puts X first. That is X's score. Then do it for 
Y and Z. Assuming X wins, all other scores will be lower than X's. The 
relationship between additional votes and Kemeny scores might not be 
obvious to the end user, though.

> - I have seen 2D graphs that show all parwise wins, e.g. in Debian. They
> are however quite difficult to draw automatically, and the positioning
> of candidates in the drawing space (e.g. higher, lower) may not be
> neutral (unless they are in one row or circle).

These can be "decluttered" by showing graphs where candidate X has an 
arrow to candidate Y iff X beats Y pairwise, otherwise there is no 
arrow. Then graph visualization programs can be used to arrange the 
candidates in a way so that candidates with more pairwise victories (or 
stronger ones, or whatnot) are closer to the top, or so that Smith set 
members always appear above non-Smith set members.

If one wants to visualize Ranked Pairs, it'd be easy to simply color the 
path throughout the graph to correspond with the pairwise 
relations/defeats picked by Ranked Pairs.

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