[EM] Voter strategising ability

[Gervase Lam]

I'm a bit concerned about the possible strategic manoeuvres that each
faction of ballots performs in the description below.

I can't see each faction unilaterally carrying such manoeuvres out.
Surely it would require thinking that is beyond the lay voter?

Alternatively, I think a candidate steering voters into the appropriate
strategic voting (as suggested in the past on this list) can be risky.
Other candidates and even the "neutral" media (e.g. editorial
reporters/commentators) would criticise the fact a that this is an abuse
of the democratic vote process (i.e. voters should vote in an entirely
sincere fashion).

Assuming that people are happy with strategic voting, then data would
need to be provided for strategising.  I expect this would be in the
form of polls/voter intention surveys being carried out market research
companies.

The voter intention surveys for the UK European 2014 elections that I
saw were more than just people answering question "who would you vote
for".  They included asking questions like how did you vote in previous
elections, age and even whether they were private or public sector
employed.

With the UK General election in mind for May 2015, the surveys included
questions that were basically on the lines of "would you vote
differently if it were the General Election tomorrow instead of the
European election and if so who would you vote for" [FYI, the answers
were generally yes to this].

I assume the "normal" person (whoever that is) would ignore the 2015
election 'poll' if they were voting in the European 2014 election.  [Why
did the surveys include the 2015 election when the one closest in time
is the 2014 election?  Well, it's because to the UK voters, the 2015 is
by far the more important.]

Also interestingly, as well as asking those surveyed who they would vote
for, most of the surveys also asked how likely they would vote in each
of the 2014 and 2015 elections on a scale from 0 to 10.  With the data
provided in most of those surveys, I would find it easy to use a
spreadsheet and use the scale to weight each vote.  Some of the surveys
did that while others only considered those who would definitely vote in
their count.

In the UK, the European count is done with multi-member districts.
However, of the four or more surveys I looked at, only one reported
their polling against the correct districts.  For the other surveys, I
only found national counts or counts for regions that only vaguely
matched the geographical districts!

Given the above, I really find it hard to see a good proportion of
voters doing the correct strategic calculations.  Also, this is only for
plurality voting!  I don't really know if voters are going to handle
rank voting strategising as per the below.

May be they could download some sort of spreadsheet from online that
could do the strategising?  But I don't think it would be flexible
enough to handle any scenario.  Also, would the voters bother checking
how the spreadsheet worked just in case a rogue spreadsheet was
downloaded?

I suppose to conclude all this, I'm just wondering if a voting method
should handle the situation where voters carry out bad strategy!!?  I
can't see any voting method being able to handle that!

A variation to the above question is, can there be a voting method that
can handle voting where each faction carries out their own strategic
voting AND can handle voting where within each faction voters carry out
their own strategic voting.  The latter may significantly be due to the
fact the voters are floating voters who don't tow the candidate/party
line.  Therefore, they would have different opinions about the other
candidates.

In this current climate, I think most voters would vote sincerely with
practically any 'reasonable' voting method.  But I don't know about the
future.  I think the voting method should be solid for the future as it
can be extremely difficult to change a voting method once one is
instituted.

Ideally, I think voters should always be voting sincerely as
strategising (both for good and badly executed strategies) makes things
complicated.  But Gibbard-Satterthwaite shows this can't happen.

Just my stream of consciousness thoughts on all this...

Thanks,
Gervase.

> [EM] Concerning Chicken Proof Smith compliant methods
> Forest Simmons fsimmons at pcc.edu 
> Fri May 9 17:48:53 PDT 2014 
        
        ________________________________________________________________
> Suppose that max(y, z) < x < y+z,  and that a sincere summary of the voter
> preferences is
> 
> x: A>C
> y: B>C
> z: C>A
> 
> These sincere preferences could not constitute an informed ballot profile.
> Why not?  Because it would not constitute a strategic equilibrium:  The A
> faction could unilaterally truncate C, and thereby win the election.
> 
> How do we know this without knowing what election method i being used?
> Well, we are assuming that the metho is chicken proof, an if so, candidate
> A would be elected wih the following ballot set:
> 
> x: A
> y: B>C
> z: C
> 
> And untruncating A in the C faction could not make A lose in any of the
> methods we have been considering, even the non-mono-raise ones like Benham
> and Woodall.
> 
> x: A
> y: B>C
> z: C>A
> 
> But this position is not a strategic equilibrium either, since th B action
> could benefit y unilaterally raising C to equal top:
> 
> x: A
> y: B=C
> z: C>A
> 
> in which case C would be the winner.
> 
> What's more, this position is a strategic equilibrium, as is the posiiion
> 
> x:A>C
> y:B=C
> z:C>A
> 
> which is just one move from the sincere preferences, and hence the most
> likely equilibrium position.  Under pefect information it is the strongest
> game theoretic solution.
> 
> In summary, if sincere preferences are
> 
> x: A>C
> y: B>C
> z: C>A,
> 
> then rational ballots will be
> 
> x: A>C
> y: B=C
> z: C>B
> 
> So the sincere Condorcet preference is also the strategic ballot CW.
> 
> 
> In general (at least in the case of three candidates) if candidate X is the
> sincere Condorcet preference, candidate X will also be the ballot CW for
> ballot voted by rational voters under complete infomation.
> 
> In particular, the ballot set
> 
> x: A>B
> y: B>C
> z: C>A
> 
> will never be voted by rational voters when there is a sincere Condorcet
> preference.  Nor will
> 
> x: A
> y: B>C
> z: C,
> 
> Why not?  Because they are not strategic equilibria, except possibly in the
> absence of any true Condorcet preference.
> 
> So why do we pay so much attention to these non-equilibrium ballot sets?
> Precisely because we want to make sure that they are not equilibrium
> positions potentially rewarding arm twisting strategy, like the chicken
> strategy.
> 
> Forest