[EM] More about Approval vs ERIRV

[MIKE OSSIPOFF]

If it were necessary to choose between Approval and ERIRV(whole), then 
ERIRV(whole) would probably be the better choice. Like ERIRV(fractional), 
ERIRV(whole) meets WDSC, and brings the added benefit of SDSC compliance, 
with AERLO. And it confers ICC & MMC compliance without the accompanying 
WDSC failure, as I was saying before. In fact, ERIRV(whole) might meet FBC, 
as I define FBC. Approval meets Alex's more demanding FBC, and maybe 
ERIRV(whole) meets that too.

If ERIRV(whole) meets FBC too, that's a lot of benefit, probably justifying 
the choice of ERIRV(whole) given a choice betwen it and Approval.

ERIRV(fractional) probably differs in not meeting FBC. There could probably 
be a situation where a voter could protect a compromise only by voting hir 
alone in 1st place. Say you know that most of your faction isn't voting 
Compromise in 1st place. But Compromise can still barely be saved by 
receiving exclusive 1st place ranking from some voters of your faction, and 
thereby getting their undivided vote.

But I haven't yet checked for demonstrations of this FBC compliance and 
noncompliance.

For me, the big failure of ERIRV, whole and fractional, is SFC. As I was 
saying before, SFC and GSFC are, to me, the best thing about Condorcet wv.

If it had to be a choice between Approval and ERIRV(fractional), the best 
choice is less obvious. If AERLO isn't included in the deal, then it's a 
choice between FBC or ICC & MMC.

In my previous posting about this, I tentatively ranked ERIRV(fractional) 
over Approval. But that isn't for sure. FBC is a good guarantee to have.  
Maybe getting ICC & MMC without losing WDSC could outweigh the loss of FBC. 
I'm not sure.

When AERLO is added, bringing SDSC compliance, that of course weighs toward 
ERIRV(fractional) in that choice. I'd probably choose ERIRV(fractional) with 
AERLO over Approval. Without AERLO it would be a more un-obvious choice.

Again,  ERIRV is an IRV mitigation compromise, and isn't as good as wv 
Condorcet. If we're going to have rank balloting, why not count it by wv 
Condorcet. Condorcet is very popular in voting system discussion, and, as I 
said, pairwise-count received a very favorable evaluation in _Scientific 
American_  recently, probably in February or March. So Condorcet looks at 
least as winnable as any rank-method. Unmittigated IRV's greater success is 
probably only the result of CVD's choice of that abyssmal method as their 
proposal.

Of course if there's interest in an actual pairwise-count proposal, it's 
important that it be a wv Condorcet proposal. Otherwise ERIRV, Bucklin, and 
Approval would be better, in comparison to a pairwise-count method other 
than wv Condorcet or a few closely related methods such as RMDD.

So if a public pairwise-count proposal turned out to be something less than 
wv Condorcet, I'd desert it for Approval, Bucklin, or ERIRV.

It would be great if CVD and other IRVers accepted ERIRV, even in fractional 
form, as a mitigation compromise. Very likely they'd like it better with 
AERLO, since its benefit then comes without actual equal rankng, and so 
ranking can be more sincere.

Mike Ossipoff

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