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fairvotereform / RankIt

https://rankit.vote
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Bar of final winner is shorter than other winners #67

Closed ggordn3r closed 4 years ago

ggordn3r commented 5 years ago

Compare "broccoli" to the other winners in screenshot. Not only is it shorter than the others, but it doesn't even visibly clear the threshold. This may be related to #35.

Non-even sizes of winner bars in bar chart, after some winners have redistributed their excess votes, and whereas the final winner only just barely made it to the threshold. https://rankit-vote.appspot.com/results/x9BtuJNjBrv3WO3Zk3F1/7 dandromb@gmail.com

Screenshot_2019-10-10 Results - pizza a third time - RankIt - Daniel Dromboski

iambateman commented 5 years ago

This is a problem of inherent to RCV with small numbers of votes.

{ "elected": [ "pineapple", "asparagus", "tomato slices", "broccoli" ], "rounds": [ { "asparagus": 4, "bacon": 2, "broccoli": 4, "chicken": 3, "feta cheese": 2, "onion": 1, "pineapple": 3, "tomato slices": 4 }, { "asparagus": 4, "bacon": 2, "broccoli": 4, "chicken": 3, "feta cheese": 2, "pineapple": 4, "tomato slices": 4 }, { "asparagus": 5, "broccoli": 4, "chicken": 3, "feta cheese": 2, "pineapple": 5, "tomato slices": 4 }, { "asparagus": 5, "broccoli": 4, "chicken": 3, "feta cheese": 2, "tomato slices": 4 }, { "broccoli": 4, "chicken": 3, "feta cheese": 2, "tomato slices": 4 }, { "broccoli": 4, "chicken": 3, "tomato slices": 6 }, { "broccoli": 4.500000000000001, "chicken": 3.4999999999999996 } ], "threshold": 5 }

The underlying data is above. We need to get to 5 to win, unless it's the last one. We've reduced all the others to exactly 20%. Broccoli has 4.

I switched it to show one decimal point, which should help: https://www.dropbox.com/s/oxi1u795bcp4t4q/Screenshot%202019-11-16%2011.26.41.jpg?dl=0

ggordn3r commented 5 years ago

I see. So the real issue is that the last winner doesn't actually have to get 20% to win, because the seat must be filled. Am I understanding that right?

If so, this is an edge case that we need to kick back to FairVote for new copy.

iambateman commented 4 years ago

I changed this to read 'In a multi-winner ranked choice voting poll with 4 winners, each winner must get at least 20% of the vote or be the last choice standing.'

In addition, we added a decimal point, which prevents it from falsely rounding up.