Maine is considering introducing preferential voting

The Something Awful Forums > Discussion > Debate & Discussion > Maine is considering introducing preferential voting

The superior voting system is This poll is closed.
First-past-the-post voting	1	1.47%
Preferential voting (IRV)	67	98.53%
Total:	68 votes

[Edit Poll (moderators only)]

Harik: Sep 9, 2001; From the hard streets of Moscow
First dog to touch the stars; Plaster Town Cop

IRV is a lot better than FPTP, but it still can come up with some surprising results. For instance, what happens in a three candidate race when the majority of the voters prefer A over B, and A over C?

pre:

4 CAB              4 CB 
3 BAC ---------->  3 BC ----> C wins
2 ACB   drop A     2 CB

Since it requires central tabulation if the winner isn't clear from everyone's first choice, you also end up in a weird situation where one candidate wins every district, but combine the districts and they lose:

pre:

Precinct 1                  Precinct 2                      Combined
Votes

6  ACB                      6  CAB                          6  ACB
4  BAC                      4  BAC                          8  BAC
3  CBA                      3  ABC                          3  CBA
                                                            6  CAB
B wins                      B wins                          3  ABC

                                                            A wins

There's some other wonky edge cases, like your preferred candidate can lose if you rank them first, but win if you rank them second. It only takes two voters switching from ABC to BCA to completely flip the election:

pre:

10 ABC            10 AC
 7 CAB ----------> 7 CA  -----> C wins
 6 BCA   drop B    6 CA

vs

 8 ABC             8 AB
 7 CAB ----------> 7 AB  -----> A wins
 8 BCA   drop C    6 BA

It's not a knock on IRV, since it's mathematically impossible to make a 'perfect' voting system. You just have to understand that there will be some weirdness and be ready to discuss why it's acceptable compared to FPTP.

ASCII charts and demonstration logic shamelessly stolen from here.

E: I forgot the weirdest one. Voting can cause your last-ranked candidate to win:

pre:

3 ABC                3 BC
4 BCA -- Drop A -->  4 BC  B wins
6 CAB                6 CB

What if two more ABC voters come out?

5 ABC                5 AC
4 BCA -- Drop B -->  4 CA  C wins
6 CAB                6 CA

_{inverted the example}

Harik fucked around with this message at 04:06 on Jun 16, 2018

# ¿ Jun 16, 2018 03:25

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The Something Awful Forums > Discussion > Debate & Discussion > Maine is considering introducing preferential voting