[EM] 3ballot / rouse idea

[Juho]

Warren Smith wrote:

> So you see the tremendous devastation this whole 3-pattern attack  
> idea can wreak.
> But in range and approval voting, all candidate scoring decision  
> are independent
> and can be on seperate "ballots" so there IS NO pattern, so not a  
> problem.
> With Condorcet, Plurality, etc, they depend and cannot be seperated
> without making ballot-validity-check impossible.

I didn't quite understand this point.

I assume that even if the three ballots are split in several smaller  
ballots, checking them all (against the rules of the voting method in  
question) at the same time would be possible. Rivest also discussed  
the option of splitting the three plurality ballots in 3r separate  
ballots ("cell-based approach").

In the preference order based methods like IRV and Condorcet there  
are some additional problems. But in such Condorcet methods that are  
based purely on a summable pairwise comparison matrix, separating the  
elements of the matrix from each others should be ok (e.g. splitting  
the three ballots in the "version #2" that was proposed by Michael  
Rouse).

On the other side, also range voting has some problems.

The content of a range ballot is rich, containing numbers e.g. from 0  
to 99. These numbers give more information to a coercer than e.g. in  
plurality and approval. What if the coercer gives the voter a set of  
9 numbers that she should use when filling the 3 ballots in a 3  
candidate election. Let's say that one of the ballots was supposed to  
be 12/34/56 but none of the ballots in the bulletin board matches  
that. The coercer can now see that the voter didn't vote as told. I  
guess one could break the range vote to three separate ballots and  
even further e.g. to 9 rows (and separate ballots) per each  
candidate, each ballot giving 0..11 points to a candidate (instead of  
the original 0..99). But that wouldn't be very practical. Anyway, the  
problem is that range ballots should be split in smaller ballots than  
e.g. approval to reach the same security level.

Juho Laatu

		
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