[EM] Ranked Preferences, example calculations

[Chris Benham]

Abd ul-Rahman Lomax wrote:

>At 06:09 AM 10/30/2006, Chris Benham wrote:
>
>  
>
>>Abd ul-Rahman Lomax wrote:
>>The strongest preference is expressed in range by rating the 
>>undesired outcome at the minimum rating and the desired outcome at 
>>the maximum rating. If the majority does this, and if they are in 
>>agreement about these two things, they will prevail.
>>    
>>
>>>"Strong preference" means strong preference for a desired outcome. 
>>>If they only have a weak preference, and express such a preference, 
>>>they might not get it.
>>>      
>>>
>>CB: This requires them to be coordinated regarding their "desired 
>>outcome". What if they agree that X should lose but are split about 
>>which individual candidate should get max. rating,
>>or  they agree that Y should win but are split about which candidate 
>>should get minimum rating? Why shouldn't they also "prevail" in those cases?
>>    
>>
>
>
>  
>
>Abd:Continually, it is assumed that the majority should "prevail," i.e, a 
>small preference by a majority should prevail over a large preference 
>of a minority, no matter how great the gap in preference, and no 
>matter how close the minority is to the majority. His argument here 
>applies equally well to Approval Voting, it is just that the matter 
>is starker there, and does require strategic considerations on the 
>part of the voter. I.e., under Approval, a voter must, to vote with 
>full power, determine an approval cutoff which involves knowing who 
>the top candidates are likely to be, and then the voter must 
>effectively state that both of them are equally preferred.
>  
>
Now voters are interested in "voting with full power" are they? In that 
case of course Range also
"requires strategic considerations on the part of the voter".

>Approval is a Range method with binary input.
>
>The majority should prevail when it is voting on a single question. 
>  
>
Why is that?  There you go again, always assuming that the majority 
should prevail!
If  a choice between Yes and No, is a "single question" then why isn't a 
choice between candidates
A and B?   And if "the majority should prevail" in a choice between two 
candidates, why not
between two factions of candidates?


>The Majority Criterion is sensible when it is a two-candidate 
>election, and both sides are informed about the preference strengths 
>of the other. 
>  
>
Assuming that the voters consider the "preference strengths" of other 
voters to be an important
issue.

>Venzke pointed out that this is what happens with 
>pizza, which is why pizza choosers don't actually use Range. They do 
>the Range work informally and then use a Supermajority criterion, 
>Approval Style, unless nobody has a strong preference, in which case 
>they will simply choose the favorite of the majority.
>
>But that informal process breaks down on a large scale. 
>
Kevin argues that it doesn't. There is enough public discussion and 
reporting of pre-polls that if
voters like the pizza choosers still think that the consensus candidate 
should win, then can pretty
easily guess who s/he is and simply voter for her/him.

What "breaks down"  from the pizza choosing scenario is that the voters 
either don't care about
the preference-strengths of other voters or they think  there are more 
important issues.

A big difference in the pizza choosing scenario is that no-one thinks 
that anyone else's pizza
preference is stupid or mistaken. Often in elections a group of voters Y 
want to over-ride the
preferences of a rival group of  voters X not because they are hostile 
to X's real interests and welfare,
but (at least in part) because they consider the X voters to be wrong 
about which candidate
would best promote that if elected.

>The Majority Criterion is weak when considering elections with more 
>than two candidates.
>
>To repeat, Chris, in his argument, continues to rely on the Majority 
>Criterion. He is using the Majority criterion to justify the Majority 
>Criterion. He is not deriving the Majority Criterion from generally 
>accepted principles that do *not* include the Majority Criterion.
>
>
>  
>
No, I have shown that the absence of  majority-related guarantees 
(including the "Majority criterion")
encourage dishonest voting by giving such voters more power to determine 
the result.  Maybe *not rewarding
dishonesty* is  one  of  your "generally accepted principles".

>I'll quote again and answer directly:
>
>  
>
>>What if they agree that X should lose but are split about which 
>>individual candidate should get max. rating,
>>or  they agree that Y should win but are split about which candidate 
>>should get minimum rating? Why shouldn't they also "prevail" in those cases?
>>    
>>
>
>They are split about the second-best. The question should be 
>reversed.
>  
>
So if you can't answer my question, just change it to one you prefer.

>Now, question is, why not just choose the candidate with the most 
>first-preference votes? I agree that the Schulze method is superior, 
>but just making the Plurality choice satisfies the Plurality 
>Criterion, which is broadly accepted, though, I think we would agree, 
>it is accepted ignorantly.
>  
>
It is obvious that you don't know what the "Plurality criterion" is.

http://wiki.electorama.com/wiki/Plurality_criterion

It is met by almost every sensible method including Schulze and IRV, and 
also some others
like Range and Approval.

>  
>
>>>He expects that people would engage in a conspiracy to vote 
>>>insincerely in order to impose their weak preference on the society.
>>>      
>>>
>>CB: What "conspiracy"?
>>    
>>
>
>An agreement to vote insincerely. "Strategically."
>  
>
What "agreement"?  If a group of people all do the same thing, like get 
out of the rain, does that mean
that there was an "agreement"?  "Agreement" and "conspiracy" implies 
that they conferred beforehand.


>
>And it *is* a control system we are engineering. The winner-take-all 
>nature of preference election systems is quite dangerous, from an 
>engineering perspective. Condorcet could make it worse, because the 
>Condorcet winner in one election might be from fanatic party A, with 
>35% of the vote, and the next one from party B, with 35% of the 
>vote.... The society swings. (And this is indeed what I think we are 
>seeing in U.S. politics. We'll see. The percentages may be about 
>right, if Condorcet were being used.)
>  
>
So according to Abd, "Condorcet could make it worse". What is "it" 
exactly?..the present system?

>  
>
>>>Right off I'll note that these votes are preposterous. People will 
>>>not vote, in such numbers, anything like this.
>>>      
>>>
>>CB: Completely irrelevant for my demonstration.
>>    
>>
>
>But what Chris is demonstrating is that Range does not satisfy the 
>Majority Criterion.
>  
>
No, I was demonstrating vulnerability to the Compromise strategy.  And  
my example wasn't "preposterous".

> 
>
>
>
>  
>
>>
>>>Well, I would have to assume that the serious closeness of this 
>>>election would be known. A shift from 98 to 99 is hardly a major shift.
>>>      
>>>
>>CB: Sufficient to force those voters to stop expressing their B>A preference.
>>    
>>
>
>Note how we have a situation where the "sincere preference" is 99 to 
>98 in Range.
>  
>
No you don't. You obviously didn't even read my not-very-long  message 
that you are replying to, or at least
you reply to bits of it before you've read all of it.

> Chris expresses this situation as "forcing" voters to 
>vote insincerely. But if they vote sincerely, with the initial 
>conditions, they get a candidate who is almost perfect to them, 
>relatively speaking. The difference is insignificant. So why are they 
>"forced" to vote the extremes, to lie about their rating of their 
>second choice? Where does this pressure come from?
>  
>
One of Abd's annoying habits is to falsely put words in my mouth. In 
none of my messages in this
thread did I use the words "forcing", "forced" or even plain "force".

>What Chris is going to have to show, if he can, and he wants to use 
>examples, is an example where social damage is done by selecting the 
>Range winner over the Majority winner, in a pure Range system.
>
>
>  
>
What constitutes "social damage" is a big somewhat subjective and 
controversial topic (and arguably
off-topic). I have in the past shown that Approval (and the 
demonstration would also apply to Range)
is very vulnerable to  disinformation campaigns.  (But I'm sure that Abd 
would find my scenario "preposterous"
and/or not a case of  "social damage").

>  
>
>>>I've recommended that Range elections include a facility for 
>>>expressing Favorite *without* giving a higher rating. I've also 
>>>recommended that Range be coarser, not 0 to 99, I'd rather see 0 to 10.
>>>      
>>>
>>CB: The fact that the range was so large (99-0) is what forced me to 
>>make the difference in size between the two factions so small.
>>    
>>
>
>Yes. However, with a larger step size (i.e, 0.1 rather than 0.01, 
>comparing Range 11 with Range 101), it is more likely that candidates 
>would rate equally. The Favorite expression option makes this less 
>painful to partisans. A 10% difference in preference strength is 
>probably still down in the noise in terms of what it means to human 
>beings. It is still a slight preference.
>  
>
I agree from the perspective of the individual voter, a "Favourite 
expression option" makes for
an improvement, but with this having no force to influence the result it 
could make the winner
look illegitimate.

>  
>
>>>Now, note that I proposed, in these and concurrent threads, a 
>>>safety feature, a runoff if the preference winner were different 
>>>      
>>>
>>>from the Range winner.
>>
>>CB: Yes *you* did, but that isn't the CRV proposal.
>>    
>>
>
>That's right. CRV has *not* in my opinion developed, yet, a consensus 
>definition of Range, as far as the details are concerned.
>
>  
>
>> I have been addressing the pure Range method, not some as yet not 
>>even fully defined "Range with Runoff" or "Range with Ratification" 
>>scheme of yours.
>>    
>>
>
>Yes. Note that these "schemes" would be normal in standard 
>deliberative process. "Shall so-and-so take office" is a not uncommon 
>motion. I'd insist on it, where I have the choice!
>
>In other words, the context of a method matters. A method which is 
>vulnerable to some possible malfunction can actually be the optimal 
>method if the context deals with that and prevents it from actually 
>causing damage.
>  
>
Since all methods are arguably "vulnerable to some possible 
malfunction", philosophically I
agree.

>  
>
>>>Remember, the "sincere" vote here was A99>B98.
>>>
>>>      
>>>
>>CB: The ranking was sincere but as I explained, the ratings maybe not.
>>    
>>
>
>We can't understand what the rankings actually mean if we do not know 
>what the sincere ranking would actually be.
>  
>
We know the "sincere rankings" just not the "sincere ratings". There is 
nothing ambiguous about
rankings.

> What Chris was allegedly 
>examining was the vulnerability of Range to strategic voting. But we 
>can't examine strategic voting unless we understand what sincere 
>voting was. The first results, 99 to 98, were presumably in the 
>absence of strategic considerations.
>
No.

> We can do nothing other than 
>assume that these are sincere.
>
>If the preference were stronger than that, why would the Range voters 
>not want to express it? 
>
Because they can only do so by reducing the voted strength of their 
stronger B>C preference and
thus increase the danger that C will win.

>  
>
>>The 18 B voters have "defected" from the AB coalition by insincerely 
>>changing from B99>A98
>>    
>>
>>>>to B99>B0=C0, and Range rewards their dishonesty (and disloyalty) 
>>>>by electing B.
>>>>        
>>>>
>>>Now, why would they do this? Only if they strongly prefer B to A. 
>>>But this contradicts the initial conditions.
>>>      
>>>
>>CB: Range only allows voters to express one "strong" (by your 
>>definition) preference (between two candidates or two sets of
>>equally-ranked candidates).
>>    
>>
>
>
>  
>
>  
>
>>>. And yet we imagine that the B voters are going to lie about their 
>>>preference, in cahoots with each other, in order to elect B?
>>>      
>>>
>>CB: Who (besides you) mentioned anything about them being "in 
>>cahoots with each other"?
>>    
>>
>
>You did. You mentioned an agreement to vote in a certain way, as I recall.
>
>  
>
>>  No coordination is needed. As long as the other factions vote the 
>>same way, individual members of the B faction can try the strategy 
>>without any risk of it back-firing (and it can work if only some of 
>>them do it.)
>>    
>>
>
>
>
>Once again, the suggested behavior makes no sense. It has been 
>constructed artificially just in order to show a characteristic of 
>Range Voting that we all agree is true. It does not satisfy the 
>Majority Criterion, and, further, a group of voters voting in highly 
>coherent patterns can push an outcome the way they want.
>
>Yes, they can. However, the point I've been making is that this is 
>essentially stupid behavior. 
>  
>
CB:Like me reading and replying to Abd's posts.

>And there is no reason to suppose that, 
>if Range Voting is implemented, such behavior will be common enough 
>to significant affect outcomes, *plus* if it *does* affect outcomes, 
>it seems that it does so in a way that is not offensive to the majority.
>
>The examples given all show election outcomes that are satisfactory 
>to the majority.
>
No they don't, for reasons I've explained.

> *Quite* satisfactory. So where is the beef?
>
>  
>
It is also at least possible that a majority believe in "majority rule", 
so the "beef" could be post-election
intense.


Chris  Benham



























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