[EM] How choice of voting systems depend on amount of participants

[Richard Fobes]

On 9/25/2014 7:46 AM, dikov dikov wrote:
 > Basically, I had an idea that upon setting a contest, one would have a
 > pull down menu with voting systems accompained with comments explaining
 > under which circumstances what system would give better results.

Describing which voting method has which characteristics is very 
challenging.  To see why, look at this table in Wikipedia:

 
http://en.wikipedia.org/wiki/Voting_system#Compliance_of_selected_systems_.28table.29

Typically when there is a choice of voting method, there is a table that 
shows who the winner is for each of the voting methods.  This is what's 
done at VoteFair.org.

 > I exactly assumed that for small polls (say 10 voters) a simple majority
 > with only one winner can be more favorable than scoring all entries in
 > ballots.

I don't understand what you mean here.

A simple majority is only assured if there are just two 
candidates/choices.  (Except in the case of a tie.)

If one of the candidates/choices gets a majority (more than half the 
votes), then all the "good" voting methods would declare that 
candidate/choice as the winner.  This means the choice of voting method 
does not matter if there is a majority winner.

The number of _choices_ (candidates) does make a big difference on the 
results.  In contrast, the number of _voters_ does not make a big 
difference (except that ties are more likely if there are a small number 
of voters).

Richard Fobes



On 9/25/2014 7:46 AM, dikov dikov wrote:
> Hello Richard,
>
> Thank you for the detailed reply.
> I exactly assumed that for small polls (say 10 voters) a simple majority
> with only one winner can be more favorable than scorring all entries in
> ballots.
> Basically, I had an idea that upon setting a contest, one would have a
> pull down menu with voting systems accompained with comments explaining
> under which circumstances what system would give better results.
>
> Thank you,
>
> Dmytro
>
>
>
> On Wednesday, September 24, 2014 11:50 PM, Richard Fobes
> <ElectionMethods at VoteFair.org> wrote:
>
>
> On 9/24/2014 4:59 PM, dikov dikov wrote:
>  > .... Since amount of
>  > voters (participants+followers) may reach even thousands I suspect that
>  > different voting mechanisms would be appropriate, depending on amount of
>  > votes.
>  > Is that right or he can stick to some systems that would be efficient on
>  > large and small scales?
>
> Thousands of voters does not cause any problem for any election method.
>
> In fact, based on my experiences with surveys/polls/elections at
> VoteFair.org, a smaller number of voters can be more of an issue.
>
> In particular, a small number of voters can more easily lead to a tie,
> and can more easily lead to the result not having a Condorcet winner.
> By contrast, a large number of voters decreases the chances of a tie,
> and increases the chances that there will be a Condorcet winner.
>
> (Clarification: Instant-runoff voting (IRV) has a limitation if ballots
> are collected at different locations, because it cannot handle the
> summarizing that works with other counting methods. Yet even IRV can
> handle tens of thousands of ballots if they are cast at a single website.)
>
> Thanks for asking, and especially thanks for learning about how voting
> should be done.
>
> Richard Fobes