[EM] Student government - what voting system to recommend?

[Abd ul-Rahman Lomax]

At 06:42 AM 4/22/2007, Tim Hull wrote:
>48% - Democrat/Pro Wrestler/Republican
>5% - Pro Wrestler/Democrat/Republican
>47% - Republican/Pro Wrestler/Democrat
>
>The pro wrestler beats the Democrat, 52-48, and the Republican 
>53-47, and thus wins. Under IRV, the Democrat would have won.  The 
>only system other than IRV that I know of that doesn't suffer this 
>issue is Range/Approval...

Most of us, I think, consider the Pro Wrestler the best winner in 
this election. Whether or not this is true, however, would depend on 
preference strengths, which are not expressed in pure ranked systems. 
If, for example, the Pro Wrestler is the first or second choice of 
all voters, and the preference strength of the Democrat over the Pro 
W. is weak for the Dems and similarly weak on the Rep side, the Pro 
Wrestler is *clearly* the best winner. And you can make it similarly 
doubtful by assuming preference strengths in the other direction.

I'm not sure which candidate Mr. Hull would prefer see win this 
election. There is majority failure. Lots of systems would then have 
a runoff between the Dem and the Rep. Which guarantees that whoever 
wins, more than half of the population would have preferred someone 
else. Not exactly a formula for unity. Some people don't value 
organizational unity, they prefer to see their own faction "win."

Consider the above election using Range:

         Dem     PW      Rep
48      10      9       0
5       5       10      0
47      0       9       10
-------------------------
sums    16      28      10

Under Range, it is not even close. And it's quite clear that this is 
an electorate that is going to be quite happy with the election of 
the PW as their governor. Yet the ranked votes are as shown above, 
exactly the same. So why would you seem to conider it obvious that 
the PW shouldn't win?

It is out of some assumption that a "compromise" candidate is weak or 
wimpy or somehow lesser than one who is the strong favorite of some 
faction. It's a familiar argument to us. And, as shown above, it can 
be totally without foundation.

The Majority Criterion, so often assumed as a basic standard for 
democracy to follow, is defective. You wouldn't use it choose pizzas, 
why use it to choose officers?

(The Majority Criterion is confused with the Majority Principle, 
which means that the majority should prevail in any deliberated 
Yes/No decision. As I have often pointed out, standard deliberative 
process, used for elections, will generally select the Condorcet 
winner, if we assume fixed preferences. In fact, preferences are not 
fixed and can shift based on how participants value maximizing the 
satisfaction of *others*, and thus we may see results that will be 
more likely to select the Range winner.)

(If you don't understand why standard deliberative process, with all 
votes being Yes/No to motions, as amended, will choose the Condorcet 
winner, then I'd suggest a little thought!) We don't use deliberative 
process to choose among multiple candidates for election because it 
is considered impractical, not because the results are considered 
inferior. If they weren't inferior, indeed, we would use "election 
methods" more widely in other applications, i.e., in selecting among 
the universe of options available for ordinary motions, such as 
motions to set a budget.)