Wednesday 23 March 2011

Alternative vote, why the 100M race comparison fails

Have you ever heard someone say something along the lines of “imagine if they did the Olympic 100m race under AV rules you could have the person who comes in third winning it”

Right now, let’s see how that analogy would actually work in the real world. 

So, you already have a series of qualifying rounds for the 100m race where the person who came third in the previous qualifier can win in the final, are they saying that that’s unfair? Assuming they are talking about the final, it’s hard to know what they mean. Are they saying that the time of the person who ran last is allocated to the other runners’ times in some way, what? Or are they suggesting that the race is run seven times and after each race the person in last place gets eliminated and the race is run again?
That would work if the presence on the track of the person who ran slowest would have had any bearing on the speed of the person that ran fastest. The analogy might work if the presence of another Jamaican on the track who finishes near the bottom was able to somehow cause the other Jamaican to slow down. Although the thing is running it 7 times would turn it into some sort of endurance event, and that’s not what the 100m sprint is meant to be. I do wonder why they don’t bring up the decathlon where the person who wins it could finish second in every event because they were able to consistently do well where other couldn’t, this also applies to the F1 championship and a tennis match where the person who wins could have scored less points overall than the looser. So in short if you want to use a sporting analogy you’re going to have to do better than that.

10 comments:

D Birkin said...

Wow, a fellow analogiser!

Ok, so the reason they do not mention that, is because AV is a single event. There is no opportunity for people to do better in some rounds and worse in others.

So, let's look at the original analogy...say in a four runner race of 100m.
The person that crossed the line first did so in 10 seconds, the runner up was 11 seconds, third was 12, and forth was 13.

The person that crossed the line first ran on average 10 metres a second.
But, they are not the winner, because forth place decides, as they didn't win, he will lend his metres a second to third place.
He ran 7.14 metres a second..and if you add that to third place, that's 8.33..therefore third place now runs 15.47 metres a second....

The person who finished over the line second is now in third place and decides to give half their metres to the (now) top two runners..
Meaning the person who crossed the line third is on just over 20 metres per second and beats the person who crossed the line first, who is only on 14.54.

Person who finished third wins.

AJUK said...

Yes that's another example that doesn't cross over well to elections.

D Birkin said...

Why's that? That is pretty much how AV works, value of lower finishers redistributed to higher, until real accomplishment is over shadowed by borrowed accomplishment

Daniel said...

AV is more analogous to a knock out competition. The person who comes last is knocked out and they race again.

Under the current system, the person in third place would have won if the person in second place hadn't entered the race, and the person in first place might lose if another contender enters the race... it's all a bit barmy.

FPTP is designed for One on One. It's why the Tory leadership contest used a form of AV to reduce to just 2 candidates before putting the vote to their party. Otherwise, why not just let the party use FPTP to vote on all four contestants?

D Birkin said...

Yes ..Fptp doesn't guarantee a Condorcet winner..and nor does AV so that's a bit of a non-argument.

AV is not closer to rounds at all. Rounds mean everyone gets to vote again..

D Birkin said...

That is the jist of AV. It sounds crazy because that is the AV system.

AJUK said...

Dan I did actually come up with an analogy similar to yours, "Are they saying that the time of the person who ran last is allocated to the other runners’ times in some way, what?" And by "what?" I was saying "Well surly they don't mean that, I'll have to give them more credit than that." But no you showed I was wrong and wrote an example like that anyway. I already admitted that AV does not guarantee a Condorcet winner, it's just more likely, but what is guaranteed is you can't get the Condorcet looser.

D Birkin said...

But that analogy is perfect for what AV is. Losers ganging up to become winners.

It's highly ..highly unlikely that Condorcet loser would win mps . Like the Elvis party etc

AJUK said...

You mean the loosers' votes, but in a race the loosers can't slow the winner down just by their presence can they?

D Birkin said...

Not quite sure what you're trying to say. In fptp you not amount of losers can change the fact they are losers.

Under AV, losers can gang up and beat winners.

There is nothing like this in sport or any other analogy open scenario.