[EM] sortition/random legislature Was: Re: language/framing quibble

[Kristofer Munsterhjelm]

Raph Frank wrote:
> On Sun, Sep 14, 2008 at 8:56 AM, Kristofer Munsterhjelm 
> <km-elmet at broadpark.no> wrote:
>> A random assembly also resists the attack where one corrupts
>> candidates, simply because it's not clear who the candidates are
>> going to be.
> 
> There is also the effect that a person who wants to be a candidate
> may need support to have any chance at all.

What do you mean?

>> I don't know if randomness, or more generally, a weak
>> voter-representative link is required for this resistance. It might
>> be, for a single given representative, but a method where voters
>> elect groups and some subset of each group is taken could also be
>> resistant to this, if it's not obvious beforehand which subset is
>> taken.
> 
> Interesting.
> 
> You could have a system with PR-STV where half of the elected 
> candidates are excluded from consideration and then the election is 
> held a second time.

One way of doing this would be to take a leaf from genetic algorithms. 
Using either roulette selection or tournament selection, pick until you 
have the council size.

Here's an example for roulette selection. The strategy would need a 
method that returns an aggregate scored (rated) ballot, where that 
aggregate is a proportional completion. Six candidates, three to be elected:

Score   Name    Cumulative score
0.9474: A       0.9474
0.6680: B       1.6154
0.3046: C       1.9200
0.2980: D       2.2180
0.1502: E       2.3682
0.0015: F       2.3697

We pick a random number on [0, 2.3697). We get 1.85603, so the first 
with cumulative score greater than 1.85603 is elected. That's C. Next, 
the random number is 2.04665. D is elected. Next, 0.738655. A is elected.

So A, C, and D are elected. The candidates with greater electoral 
support have greater chance of being chosen, but for any candidate, 
there's still a nonzero probability that some other will be selected 
instead.
By running the scores through a function, one could make the method 
regard the electoral results more (by amplifying the gaps in scores) or 
less (by evening them out).


However, in general, there's a problem with such hybrids. The problem is 
that, for elections to work, the people must know the candidates to at 
least some extent. Because of this, candidates are going to have a 
history - they will be persistent, and some candidates will run multiple 
times. But this means that they can be corrupted, since the hypothetical 
conspiracy know who to target. If you elect groups instead (or parties), 
the conspiracy or lobbyists are going to target those who decide the 
group composition - the party management in the case of parties. The 
effect will lessen if there are many groups, or the method supports 
independents, but it won't disappear.

There seems to be an inescapable tradeoff here, at least unless one 
"thinks outside the box", like with delegable proxy.