[EM] Single Winner Systems categorization

[Adam Tarr]

Tom,

sorry I didn't respond earlier - I've been to busy for EM stuff lately.

This setup is, broadly speaking, acceptable to me.  "One Choice" voting 
seems well defined enough.  Given this categorization, I have no problem 
with putting Approval in the rated ballot section.

I only have one significant objection - the use of "sequential rounds" as a 
sub-category.  I don't think it's a good term for either "One Choice" 
methods or "Ranked Choice" methods.  I just don't think "round" is well 
defined in this case.

For one choice methods, a better term would be something like "successive 
balloting" or something else that clearly indicates a physical return to 
the polls.

In the ranked choice methods, I still maintain that the sequential rounds 
section is not really meaningful.  As I said earlier, I can create a 
Condorcet-compliant method that has sequential elimination, and I can even 
write out approval or Borda so that they will have elimination rounds.  Do 
those three methods really need their own sub-category?

Also, Proportional Approval Voting (PAV) should be included among 
distributed proportional methods.

-Adam