[EM] new working paper: "Four Condorcet-Hare hybrid methods for single-winner elections"

[James Green-Armytage]

Hi Kristofer,

Thank you very much for the thoughtful comments. Some replies follow.

Kristofer wrote:
?Regarding most strategies being burial or compromising: I seem to recall
that in your previous paper, that was the case for most methods, but not
for Hare (IRV) and top-two runoff. For the sake of completion, you might
want to say that although other strategies are possible, IRV and
Alternative Smith do better (are more resistant) than the other methods
even when those are included. Thus the readers know it's not just a case
of the resistant methods "reorienting their weak spots" away from burial
and compromising.?

I reply:
A few things here.
1.  The relevant table in the SVN paper is called ?simple strategic  
opportunities, as share of all opportunities?. Even in IRV, the  
burying/compromising combination does account for ?most?  
opportunities, i.e. >50%. And overall (across methods), it accounts  
for something like 80% upward, depending on the model.
2. In the current Four Methods paper, I?m actually not limiting  
strategies to burying and compromising; rather I?m just limiting it to  
situations in which all members of the coalition cast the same ballot.  
So, I just wanted to be clear about that. I admit, though, that this  
restriction probably does make ?push-over? strategies impractical,  
which is good for Hare.
3. You?re probably right, in that it might be good to mention that  
Hare?s performance holds up without this restriction, though I can't  
say the same thing for sure about the Condorcet-Hare hybrids.

Kristofer wrote:
?I was going to suggest including ANES simulations, but that could make
the strategy part of the paper too cluttered. Perhaps mention that ANES
(which are notable because they're based on real data) also show that
the Condorcet-Hare methods resist strategy well.?

I reply:
Good point. I agree that I should probably mention this.

Kristofer wrote:
?Some other observations: it seems that adding a Smith constraint (Smith,
or Smith//) limits the vulnerability to compromising, and that having
the base method satisfy LNHarm greatly limits vulnerability to burial,
since the base method is then immune to burial.?

Yes... this is kind of what I?m trying to say at the end of the  
strategic voting section. Maybe I could explain it better?...

Kristofer wrote:
?If that's right, Smith-constrained methods based on LNHarm methods could
be interesting. They would either show great strategy resistance, or
they would show that LNHarm is not enough (e.g. since Smith can't pass
LNHarm, what it does let through may line up wrong). So comparing
something like Smith/Plurality or Smith/DSC to the Condorcet-Hare
methods could give more information either way. I may do it if I ever
get around to implementing your strategy tests.?

These are definitely interesting ideas, though as Kevin pointed out,  
DSC isn?t immune to burying. I?ll expand on this in a separate thread.

my best,
James