[EM] Notes on a few Later-no-harm methods

[Richard Lung]

On 12/05/2022 20:12, Richard Lung wrote:
>
> K.M.
>
> I don't recognise this description of Binomial STV. Which is based on 
> keep values, which is as much to say it is not never no-how based 
> solely on first preferences and last preferences. (Even in 
> single-winner elections.
>
> Keep values can be used even when Gregory method is not, in 
> traditional STV, reduced to the single winner case. That is because 
> BSTV extends the use of keep values beyond Meek method, to candidates 
> in deficit of a quota, and to exclusion keep values, as well as 
> election keep values.
>
>   Keep values are not like Borda count. It is no 1st choice advantage 
> to desist from later preferences. The keep values merely record what's 
> done as true intent.
>
> BSTV uses all the preferential information, rationally counted (good 
> book-keeping), not assumed weights, which may or may not be true, and 
> therefore might be considered fair game.
>
> Regards,
>
> Richard Lung.
>
>
> On 11/05/2022 22:48, Kristofer Munsterhjelm wrote:
>> On 11.05.2022 19:32, Richard Lung wrote:
>>> Binomial STV is a later-no-harm method. It is also monotonic. It is
>>> a both elective and exclusive rational count.
>> In the full preferences case, single-winner Binomial STV in effect works
>> by letting each candidate's score be the number of first preferences
>> divided by the number of last preferences, and then electing the
>> candidate with the highest score.
>>
>> Later-no-harm is about what happens when you add rankings to an
>> incomplete ballot, e.g. going from
>>
>> A>B
>>
>> to
>>
>> A>B>C.
>>
>> Now suppose we have a three-candidate single-winner election, and
>> suppose the ballots are, just as an example:
>>
>> 3: A>B>C
>> 5: A>C
>> 13: C
>>
>> How many last preferences does Binomial STV count A, B, and C as having?
>>
>> And for the sake of completeness, in the election:
>>
>> 3: A=B>C
>> 5: B=C>A
>> 13: C=A>B
>>
>> How many first preferences do A, B, and C have according to Binomial STV?
>>
>> -km