[EM] Approval-enhanced IRV (take 2)

[Toby Pereira]

 But of course, as with STAR, any complex add-on to the method is unlikely to ever be adopted, regardless of how much better it is in theory...
Toby
    On Wednesday, 23 August 2023 at 06:59:06 BST, C.Benham <cbenham at adam.com.au> wrote:  
 
  
Forest,
 
 I'm glad you approve.
 
 

 So if a voter was giving out too much approval by approving below one of the mandatory semi-finalists, the method fixes that faux pas for free! 
  
 
 Also the voter might not be making the innocent "mistake" of risking the IRV winner being defeated in the final by a candidate they like less, but
 could be trying a relatively easy and tempting Push-over strategy.
 
 Chris
 
 On 23/08/2023 8:54 am, Forest Simmons wrote:
  
 
 
 
  On Mon, Aug 21, 2023, 9:36 AM C.Benham <cbenham at adam.com.au> wrote:
  

 This is I think more appealing and streamlined than my earlier version.
 
 *Voter strictly rank from the top however many candidates they wish.
 
 Also they can mark one candidate as the highest ranked candidate they 
 approve.
 
 Default approval is only for the top-ranked candidate.
 
 Determine the IRV winner.
 
 On ballots that approve the IRV winner, approval for any candidate or 
 candidates
 ranked below the IRV winner is withdrawn.
 
 Elect the pairwise winner between the (thus modified) approval winner 
 and the IRV
 winner.*
 
   
  So if a voter was giving out too much approval by approving below one of the mandatory semi-finalists, the method fixes that faux pas for free! 
  What if the approval cutoff were simply moved adjacent to the IRV winner? 
  That would probably give the IRV winner's strongest defeater too much help, and wrest too much control of the approval lever from the sovereign voters. 
   It looks like you are treating the malady with the minimal effective dose of the right medicine! 
  Great!  
  Who will spread the good news?   
 
 This works fine in the same way as the earlier version in the example 
 given to talk
 about Minimal Defense and Chicken Dilemma.
 
 It is more Condorcet efficient than normal IRV, and meets (or comes 
 close enough
 to meeting) appropriately modified versions of the LNHs and Minimal Defense
 and Chicken Dilemma.
 
 49 A  (sincere might be A>B)
 24 B   (sincere might be B>C)
 27 C>B
 
 If the C voters B>A preference is strong they can by approving B avoid 
 regret for not Compromising.
 
 Then the final pairwise comparison will be between B and A and B will win.
 
 But if they are more concerned about not letting the B voters steal the 
 election from them by possible Defection strategy then they can do that by not 
 approving B.
 
 49 A>C>>B
 48 B>>C>A
 03 C>A>>B
 
 Say this is for a seat in Parliament, and the voters have been 
 accustomed to using FPP,
 IRV or Top-Two Runoff. It would cross the mind of no-one that the 
 "Condorcet winner"
 C should defeat the IRV (and FPP and even Approval) winner A.
 
 But according to Condorcet advocates the B voters should or could be 
 regretting no getting an outcome they somewhat prefer by all top voting C.
 
 Well with this system the B and C voters together can "fix" this without 
 anyone betraying their favourites or reversing any sincere preferences simply by all of 
 them approving C and not A.  Then the final pairwise comparison will be between C and A 
 with C winning.
 
 Chris Benham
 
 
      
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20230823/2da33f17/attachment-0001.htm>