[EM] Anyone got a good analysis on limitations of approval and range voting?

[Jonathan Lundell]

On Nov 7, 2009, at 12:12 PM, Matthew Welland wrote:

> It seems to me that approval and range voting eliminate most of the
> strategic opportunity in single winner elections and the marginal
> improvement of other methods is fairly small. Can anyone point me to
> analysis, preferably at a layman level, that contradicts or supports  
> this
> assertion?
>
> Or, in succinct terms, what are the strategic flaws in approval or  
> range
> voting?

Voting in either one is fundamentally strategic.

Take the simple case of casting an approval ballot with three  
candidates where your ordinal preference is A>B>C. Obviously you vote  
for A and not for C. The strategic question is whether you vote for B.  
Voting for B might cause B to beat A, but on the other hand it could  
cause B to beat C (depending of course on the other voters).

Presumably your decision to vote for B or not will be driven by your  
best guess as to which of those is more likely, and might also be  
influenced by whether your preference is more like A>>B>C or A>B>>C.  
The closer you are to A=B>C or A>B=C (and the better your information  
about other voters, say from pre-election polling), the easier that  
decision might be, but it's a strategic decision.

I suppose that I end up more or less in the same came as RB-J, except  
that I (mildly) prefer STV to Condorcet methods. In either of those,  
it's easy to cast a sincere ballot, and it's usually a good, or at  
least acceptable, strategy to do that. With approval or range, you  
don't really have that option: every ballot is inherently a strategic  
one.