[EM] Meta-criteria 9 of 9: Conclusion

[Juho]

On May 7, 2010, at 12:20 AM, Jameson Quinn wrote:

> Finally, I come to the end of this series. To conclude, let me  
> return to the initial question which started me down this path: what  
> do the values and heuristics have to say about voting system criteria?
>
> Utility (that is, outcome social utility) is a unique value in that  
> we have a single clear tool for analysis: Bayesian regret  
> simulations. The only two things we need are a model for voter  
> utilities - which should have only weak, linear effects on the  
> performance of a given system - and a model for voter strategy. I  
> hope that my analysis of strategy helps us get the latter. And  
> meanwhile, I hope that the outstanding issues of strategy, along  
> with the issues of expressivity, legitimacy, and cost, can help the  
> partisans of Bayesian regret analysis (a group in which I weakly  
> include myself) be humble about the results so far.

Since the world of measuring personal and group utilities is very  
complex I find it useful to sometimes simplify things by fist naming  
the targets and assumptions and then comparing the candidate methods  
against this simplified model.

When trying to measure the true utilities one often sets some limiting  
assumptions like utilities that are normalized to some given range of  
values. One may also have different targets in different elections.  
Sometimes one wants to maximize the sum of utilities, sometimes  
maximize the smallest personal utility. One could also have some more  
sophisticated functions that e.g. try to lift the utility of 90% of  
the voters/citizens to some agreed/ideal level.

Models that are based on rankings are simplified and practical models  
of the world. It is interesting that often such models are considered  
to be ideal. I mean that for example the majority principle is taken  
as granted although it can be seen to violate some underlying utility  
principles (the minority might have stronger opinions). But models  
agreed by the society and well working models (that can e.g. handle  
strategic temptations) have a value of their own and therefore may be  
adopted as "values".

For these reasons (complexity and debatability of the true utilities,  
different needs in different elections, assumptions on the society  
(competitiveness, morale, traditions), influence of models that we  
have created ourselves, need to meet also some (irrational)  
marketability ad perception related needs) it may often be enough to  
just state the targets and assumptions (the model to be used) and then  
try to implement that using some concrete method. The value of the  
model (targets, assumptions) and the properties of the method (that  
tries to implement the targets) can then be discussed separately.

>
> The criteria that relate to expressivity are mainly participation,  
> consistency, and related criteria. There is a certain fundamental  
> tension between expressive freedom and outcome utility in a decisive  
> system. Ballots which give a large degree of decisive freedom to  
> voters inevitably involve strategic tradeoffs between utility and  
> expressivity. Perhaps one way to resolve this is to make a hybrid  
> system, which is part election and part nonbinding poll. The  
> election part would strictly limit voter freedom in order to  
> eliminate strategic concerns; two-rank Bucklin is one possible  
> example of the limited freedom I'm imagining. And the poll part -  
> probably based on Range, for maximum freedom - would allow free  
> expressiveness; while it wouldn't be binding, to keep stratgic  
> concerns from taking over, it would certainly affect a candidate's  
> mandate. The poll would be optional; a simple Bucklin vote would be  
> counted with some default assumptions about what that means in Range  
> terms. Maybe you could even give marginal impact to the poll without  
> making it too strategic. For instance, if you were building a polity  
> from scratch, the rule could be that a Bucklin winner is elected,  
> and if they're also a Range winner they get an extra year on their  
> term; or that the Range winner gets to appoint the attorney general;  
> or some such marginal importance for the poll.

Note that in competitive environments also pure polls may get  
strategic. If we have first a poll and then an Approval election it  
might make sense to give strategic answers in the poll to make my  
Approval favourite look stronger than some other candidate in order to  
make the supporters of that other candidate approve also my favourite  
(since the strategic advice in Approval will be to approve at least  
one of the leading candidates). Also in other elections people tend to  
vote for strong candidates / potential winners.

>
> The criteria that relate to legitimacy are participation;  
> consistency; and clone-, strategy-, and fraud- resistance criteria.
>
> The main criterion that relates to cost is one-round decisiveness.

(Maybe also time and effort to count and verify the results, and need  
to buy voting machines, and maybe also need to debate about the  
results after the elections.)

Juho


>
> The heuristics relate to various criteria, but in another sense they  
> function as vague criteria themselves.
>
> I'll repeat my conclusion to the long section on strategy here, too.  
> Strategy's biggest effects are not on outcome social utility, but on  
> legitimacy and expressivity. I believe that these effects are  
> serious and worth avoiding. Cabal strategy seems to me the best  
> model for strategy analysis, but if it isn't going to get hung up on  
> all Condorcet ties being strategic, it needs to include factors  
> which affect the likeliness of strategy actually being used. These  
> factors include motivation, implied dishonesty, and necessary  
> participation.
>
> Finally, for those who have read through this nearly endless  
> treatise, thank you for your patience. I hope that I've said enough  
> to make it worthwhile. I also hope that I start more than one  
> productive discussion - productive enough to change my mind about  
> some aspects of what I said. My ultimate hope is that this kind of  
> discussion will help us have the perspective to recognize, to  
> design, to evaluate, and finally to begin to agree on the best  
> possible voting systems. The more big-picture perspective we have  
> and share, the more we will become an activist force with which  
> nations must reckon.
> ----
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