Mar 5, 2010

how does instant runoff work anyway?

three of us wanted to watch a movie together at my house.
i had 4 movies, one of which i had seen already but was willing to see again.
call it movie A.

so we decided to do an instant run-off.
each took paper and pen and listed the movies by preference.
number one was the one we most wanted to see, and number 4 that we least wanted to see.
it ended up like this:

1. A, B, C

2. A, D, D

3. B, B, C

4. A, C, D

we couldn't figure out what to do next, with no clear winner!
we added together the rankings of each movie, for example A had 1 + 2 + 4 = 7.
this gave us a tie between A and B and between C and D.
once again we were stumped.

i had put movie A last, since i'd already seen it, but i said i'd watch it again, so we did.
the movie was UP. it was just as much fun the second time around!
but we're still wondering how we could have made that work!

1 comment:

  1. This is confusing because you clearly have four movies, but only three choices for favorites. The majority wanted A, so you made the right choice.

    In my mind an instant runoff requires a larger number of voters and fewer choices; it is a tie-breaker vote.

    Say you have candidates A, B, C, D, and E. The voting shows A and C received 15 votes each and the other 15 votes are split between the other candidates. So the lesser candidates are eliminated, and all 45 voters choose between the two leaders. Unless there is a totally even number of voters, someone will win.