# [EM] Fwd: U/P voting: new name for simple 3-level method.

C.Benham cbenham at adam.com.au
Thu Sep 8 14:13:07 PDT 2016

```C: But above you are suggesting that U/P somehow uses a both a 2-slot
ballot and a 3-slot ballot. Which is it?

J:3 slots. Where and how do I suggest otherwise?

C: I pasted in where you wrote (in a message you said I was free to send
to EM) this:

> J: "On the 3-slot ballots, they vote A>B. On the 2-slot ballots, they
> vote A. These are perfectly consistent."

C: That was in response to me asking you how, in an example you gave,
how some voters were able to vote one
"unacceptable" candidate above another (they voted A>>B>C).

J: In MTA, if no candidate is majority preferred and several are
majority approved/acceptable, the most approved wins.

C: No, that is MCA.

MTA says that if the most top-rated candidate is top-rated by a majority
then s/he wins, otherwise if more than one candidate
is approved (voted above bottom) on a majority of ballots then the one
of them that is most top-rated wins, otherwise the most
approved candidate wins.

And I now notice that is that last clause that makes it different from
U/P.  When no candidate is majority approved it can give
a different result.

I would say usually the Approval winner pairwise-beats the Top-Ratings
winner, and of course is  more "broadly supported".

MTA (with default rating bottom) I think is my favourite of the methods
that fail Irrelevant Ballots.

Chris Benham

On 9/9/2016 4:58 AM, Jameson Quinn wrote:
>
>
>
>>         C:  Again, I'd be interested in seeing a plausible example of
>>         when U/P doesn't elect the Approval winner.
>>
>>         Easy.
>>         20: A>>B>C
>>         35: B>A>>C
>>         45: C>>A=B
>>
>>         Threshold in approval is >>. In U/P, voters are as expressive
>>         as possible.
>>
>>
>>     C: On 3-slot ratings ballots, how are the 20 A supporters able to
>>     vote one unapproved candidate above the other?
>
>>     On the 3-slot ballots, they vote A>B. On the 2-slot ballots, they
>>     vote A. These are perfectly consistent.
>
>     C: But above you are suggesting that U/P somehow uses a both a
>     2-slot ballot and a 3-slot ballot.  Which is it?
>
>
> 3 slots. Where and how do I suggest otherwise?
>
>
>     Actually it seems to me that the stripped-down 3-slot version (if
>     default rating is "Unacceptable") is actually the same method
>     as MTA. "Unacceptable" is just the inverse of "Approved".  Any
>     candidate who doesn't get a majority "Unacceptable" score must
>     get a majority Approval score.
>
>
> Not the same. In MTA, if no candidate is majority preferred and
> several are majority approved/acceptable, the most approved wins; in
> U/P, the most preferred wins. This is the only difference, aside from
> secondary issues like ballot design. I believe U/P is better in this
> case as it makes a chicken strategy harder to pull off successfully; a
> clean cliff rather than a slippery slope.
>
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