字幕表 動画を再生する 英語字幕をプリント Queen Lion of the Animal Kingdom is displeased. She recently introduced elections for the office of king using the first post the post voting system. While her Realm started out as a healthy democracy with many parties running candidates for king, it quickly devolved into two party rule, with the citizens not liking either one but trapped within the system because of a problem called the spoiler effect. However, one of Queen Lion’s subjects from a distant land, Wallaby, has a solution: The Alternative Vote. What’s the difference? To find out, lets follow one voter on election day, Red Squirrel, under both systems. There are five candidates running for king, two members of the big parties Gorilla and Leopard and three other candidates, Turtle, Owl and Tiger. Under first-past-the-post Red Squirrel gets a ballot where he picks just one candidate. Red Squirrel Really likes Turtle and even campaigned for him. However he knows that his new neighbor, Grey Squirrel, is voting Gorilla. And what, starts to wonder Red Squirrel, about all the other animals? Who are they going to vote for? The debates on Animal News Network only had the big parties, so Red Squirrel thinks it’s going to be a close race between Gorilla and Leopard. While he’s indifferent toward Gorilla he is deathly afraid of Leopard. Because he can only pick a single candidate, he gives his one vote to Gorilla in hopes of preventing Leopard from becoming king. This is strategic voting, and it’s a necessity under First Past the Post. But now it’s time to look at the Alternative Vote, which wallaby explains to Red Squirrel. Instead of picking one and only one candidate, he can rank them in order of his most favorite to his least. He goes into the voting both and gets the same ballot as before, but now puts Turtle as his first choice, Owl as his second and Gorilla, third. He dislikes Leopard and Tiger equally so he stops filling in his ballot and drops it in the box. At this point, Red Squirrel doesn’t care exactly what happens, he has other things on his mind and heads off. But you, dear citizen, want to know how the votes are counted so here goes: Turtle, beloved though he is with some of the citizenry, comes in last place with only 5% and he is eliminated from the race. Because the voters ranked their candidates in order, we can know what would have happened if Turtle didn’t run. Without Turtle, voters like Red Squirrel, would have picked Owl instead, so their votes are transferred to her as though Turtle was never in the race at all. This is why Alternative Vote is sometimes called Instant Runoff Voting. It’s able to simulate a bunch of elections where the least popular candidate is eliminated after each round without all the time and expense it would take to run a bunch of campaigns, one after another. The Alternative Vote method keeps eliminated the least popular candidate until someone either wins a majority or is the only one left. As no one has a majority yet, the next lowest candidate, Tiger, is eliminated. Tiger voters listed leopard as their second choice, so she gets Tiger’s votes. In the last round, Gorilla is eliminated. Gorilla voters listed Owl as their second choice, so Owl gets those votes, wins a majority, so is crowed king. The alternative vote is a better system because it produces winners that a larger number of voters agree on. While the Alternative Vote does have flaws it’s important to note that any problem AV has, first past the post shares. They’re both susceptible to gerrymandering, they aren’t proportional systems, they can’t guarantee a Condorcet winner (which math geeks hate but there isn’t time to explain here), and over time they both trend toward two main parties. That being said, Alternative Vote has a huge advantage that first past the post lacks and makes it a mathematically superior method: no spoiler effect! Imagine this election: the two big candidates are running, Gorilla and Leopard, and Leopard looks set to win 55% to 45%. But then a third party candidate, Tiger, enters. Tiger manages to convince 15% of the Leopard voters to back him. Now the results are: Under first past the post, gorilla now wins even though a majority of the voters didn’t want him. Under the Alternative Vote, because all Tiger voters put Leopard as second choice, Leopard still wins because a majority of the citizens of the animal kingdom would rather have her in charge than gorilla. With AV citizens can help support and grow smaller parties that they agree without worrying they’ll put someone they don’t like into office. After examining the differences, Queen Lion decrees that the Alternative Vote is to be the rule of the land for electing the king and everyone is happier. …well almost everyone. The two big parties can’t be complacent and need to campaign harder for their votes. This has been The Alternative Vote Explained by me C. G. P. Grey. Thank you very much for watching.