[EM] IRV vs Plurality (Dave Ketchum)

[Kristofer Munsterhjelm]

Kathy Dopp wrote:
> On Sat, Jan 16, 2010 at 2:54 PM, Abd ul-Rahman Lomax
> <abd at lomaxdesign.com> wrote:
>> results. Generally, voting security people like to use audits that select a
>> sample of votes and look for errors, then they use statistical analysis to
>> estimate the overall error in result probability. That's not nearly as easy
>> with IRV, because IRV is a chaotic method, sensitive to a single vote error
>> that ripples into shifting many votes. With many places where that single
>> vote error can occur.
>>
>> At least that's my understanding, I'd defer to Kathy on this!
> 
> Yes, IRV is virtually impossible (practically) to audit in a way that
> the general public could understand. There are several ways to
> manually audit IRV/STV as far as publicly reporting the tallies and
> randomly selecting them:
> 
> 1. report every rank choice ballot for every voter and make a humanly
> readable mark on every ballot (preferrably after the voter casts or as
> the voter casts the ballot to avoid vote-buying) that is also listed
> alongside the ballot choices, and then randomly select ballots, or
> 
> 2. publicly report all the tallies for each possible unique rank
> choice vote for each precinct (a huge number larger than the number of
> voters who vote in most precincts if there are many candidates
> running), and then randomly sample from those, or
> 
> 3. manually count 100% of the ballots

Offtopic, perhaps, but would these problems hold for Condorcet as well? 
Both IRV and Condorcet methods are ranked-ballot ones, though I guess 
auditing Condorcet would be easier since it's precinct-summable. It 
doesn't appear to be as easy as Plurality, though, because you can't tie 
"A beat B N times" to what kind of votes the N voters submitted other 
than that they ranked A ahead of B.