[Election-Methods] Plurality vs A/R/I/C/Other

[Dave Ketchum]

I will talk of these in the order listed: Plurality, Approval, Range, IRV, 
and Condorcet.  Other is simply any other method - which do not get 
discussed because I have not heard of them as competitive with those 
discussed.

Three candidates:
      H(ot) - I WANT this one to win.
      C(old) - I WANT this one to lose.
      W(arm) - better than C, but not as good as H.

Plurality:
      What is used in most US elections.
      Satisfies most voters' thinking most of the time.
      BUT, makes trouble by too many failures as to letting voters express 
their desires in some elections.
           NEED to permit thinking to be expressed more completely for, 
besides satisfying these voters, this can affect who wins.
           NEED to let Plurality thinking be expressed easily, for this 
will please most voters most of the time.
      NEEDS runoffs to recover when there is no clear majority winner
           Gives voters a second chance when their first vote was not for 
one of the leaders.
           Can be inadequate for, as the French demonstrated in a 
presidential election, multiple agreeable candidates can split their votes 
to let fringe candidates come in first and second in the election.
      Some examples:
           Gore vs Bush:  A near tie.  Those who voted for Nader, etc., 
could likely have affected who won if choosing between Gore and Bush was 
also permitted to them.
           McCain vs Clinton and Obama:  Could be all three plus others on 
some ballots this November - worse than Gore vs Bush!
           Village election in which I will vote this Tuesday:  Three 
candidates for mayor:  Current mayor vs TWO wannabe replacements. 
Headache for those like me who see C vs W vs H.

Approval:  A bit better than Plurality, and trivial to implement:
      Can vote H+W over C, but not at the same time as satisfying my 
Plurality desire to vote H over W+C.
      Often there is not even a hopefully useful poll to help me guess 
which way to go this time.

Range:  A considerable increase in complexity offered to voters and 
imposed on counters; not clear that the value improvement is worth it.
      Given a rating scale of 0-99, voters would logically rate H at 99 
and C at 0.  Many advise rating W with H or C (99 or 0) for same reasons 
as for Approval - which gives no benefit for the complexity.
      Counting, if done by hand, gets to be labor for the ratings assigned 
by each voter must be summed.

IRV:  While using the same ballot as Condorcet, and usually agreeing as to 
winner, its different counting method can disagree:
      Spoilers:  While discarding candidates for having least first choice 
votes, IRV can discard the Condorcet winner because, while the winner is 
better liked than the next in line, the better liking would not be visible 
without looking at remaining ballots.
      Cycles:  While these are a visible pain to resolve in Condorcet, 
they represent near ties with IRV selecting any one by luck.

Condorcet:  Some claim more complexity than for Range.  I counter that any 
such is rewarded with better value:
      Voting:
           Rank best liked at top; rank any equally liked the same.  These 
are the ones that would be voted for in Plurality or Approval.
           If more are liked enough, rank those best liked among them at 
next rank.  Repeat as desired.
      Counting:
           Can sort per top rank.  If more than half agree as to 
candidate, this is winner.
           Can do full count as in a tournament.  For each pair of 
candidates, x and y, how many voted x>y and how many y>x.
                NOTE that inequalities are ALL that are tested for. 
Magnitude of difference in rank matters not; unranked is below the lowest 
voter rank.
                If any candidate x beat all the ys, x wins.
                Else there is a cycle such as A>B>C>A and the near tie 
must be analyzed to decide on winner.
-- 
  davek at clarityconnect.com    people.clarityconnect.com/webpages3/davek
  Dave Ketchum   108 Halstead Ave, Owego, NY  13827-1708   607-687-5026
            Do to no one what you would not want done to you.
                  If you want peace, work for justice.