[EM] voting strategy with rank-order-with-equality ballots

[Kristofer Munsterhjelm]

Chris Benham wrote:

> The trouble is, range voting is simple. Simple enough that you can
> reach a pretty full understanding of what strategic range voting is.
>   (Which is not at all trivial,
> but it can pretty much be done.) In contrast, a lot of Condorcet
> systems including Schulze are complicated. Complicated enough that
> making confident statements
> about their behavior with strtagic voters (or even undertsnading what
> strtagy IS) is
> hard.

Another problem is, you can use this to argue in favor of either side. 
If strategy is easy, then you can say that everybody can do it and thus 
the information content will be seriously degraded, leading to odd 
results. On the other hand, if strategy is hard, then you can say that 
the parties will crunch the numbers to find out what strategy will 
indeed work, and tell their voters to vote in this fashion, something 
which will unbalance power in favor of the large established groups.

On top of all of that, people don't strategize maximally. In other 
words, they're not perfectly rational. In some sense, that shouldn't be 
unexpected, since if people were rational, turnout would be extremely 
low (yet it isn't). However, it does muddy the waters further.

Basically, there seems to be two types of strategy. The first is that 
which anybody can do (exaggerating in Range) - let's call that tactical 
voting. The second is that which parties coordinate - let's call that 
vote management. The actual voting method weaknesses that are used may 
be the same (see Schulze's claim that vote management in STV is just 
coordinated Hylland free riding, for instance), or they may differ.

Perhaps one could make an argument that methods where strategy is harder 
to pull off is better (even if no method is strategyproof) like this: as 
regards tactical voting, the argument is simple - harder strategy will 
make it more difficult for people to figure out the optimal strategic 
vote. As regards vote management, parties that make too extensive plans 
would be faced with social disapproval from not "playing fair", 
therefore methods that require complex strategies would less often be 
exploited. The latter point depends on whether employing strategy is 
frowned upon or accepted -- one may see an example in that when New York 
used STV, the Republican and Democratic parties used as much vote 
management as they could muster, whereas in other countries, vote 
management is uncommon.