[EM] [CES #4429] Looking at Condorcet

[Juho Laatu]

On 2.2.2012, at 21.07, Kristofer Munsterhjelm wrote:

> On 02/02/2012 05:28 AM, Jameson Quinn wrote:
> 
>> I honestly think that honest rating is easier than honest ranking.
>> (How's that for honesty per square word?) MJ is the only system which
>> allows honest rating to be full-strength in practice; and SODA is the
>> only good system which allows anything easier. (And no, approval is not
>> easier than MJ, because approval forces some amount of strategizing.)
> 
> As a contrast, to me, ranking is easier than rating. When I'm set to rate, I tend to think about whether I rated the candidate just right or not - did I rate him too high, too low? - but if I rank, I don't have to care about that. All I have to do is get a general idea of the order of preference, and then ask "do I like X better than Y or vice versa".
> 
> Maybe I'm uncommon, but I thought I would say it. I've heard the claim that rating is easier than ranking before, and maybe it still is -- to most people.
> 
> I'll also note that many of the ranked voting methods can be also be applied even if the only information you can get from the voters or  the system is "is X better than Y" for pairs {X,Y}. Thus, these can be used to determine winners in actual one-on-one contests (e.g. chess matches, kittenwar-style preference elicitation) where it would be hard to use ratings.

I agree that it is very difficult to claim that rating would be easier than ranking. Let's see what I can do.

Attempt 1: It is difficult to write something like "a>b>c" on the ballot paper, or to push buttons of the voting machine so that all the candidates will be in the correct order.

Answer 1: Don't use such procedures. If you want to be sure that ranking at least as easy as rating, use same ballots as with rating. You can derive rankings from them.

Attempt 2: Methods that do not allow equal ranking can not use rating style ballots.

Answer 2: Use better methods or use rating style ballots and split the vote in two parts (or use random order).

Attempt 3: If there are very many candidates, it is easier and faster to rate them individually, one by one, rather than compare every candidate pairwise to others.

Answer 3: You can do this with rankings too if you are not interested in determining the preference order of those candidates that are almost equally good. Fast rating is also inaccurate in the sense that one may give more points to A than B although A is worse than B.

Attempt 4: People have used numbers and ratings in schools.

Answer 4: Think that you are still in the school and just rate the candidates (ratings will be derived from those ratings).

All the arguments are actually based on the fact that rankings can be derived from ratings. In the case of rankings the voter need not care about the scale of numbers that one uses (1,2,3 is as good as 1,49,50).

Juho