Thursday 4 October 2012

Heresthetics and the alcohol purchase age

I lost about $300 on iPredict a little over a month ago. I had really strong expectations that the Government's bill proposing a split alcohol purchase age was going to pass. Standard rules of order seemed to ensure that the government's bill would pass. The amendment to keep it 18 would fail as all those preferring Split or 20 would vote it down; the same would hold in reverse for the amendment to increase the age to 20 across the board.

As we all know, Parliament decided at the last minute to change the normal procedure for this bill and this bill only. Instead of the normal rules of order, Parliament voted for the three options on first preferences. Then, the one with the fewest votes was dropped. So the Split option was dropped and we were left with the head-to-head contest between 18 and 20, won by 18. It's remarkable. Split looked like it was a Condorcet winner. And, had the "increase it to 20" group had their act together, the outcome still would have been Split: they'd have counted noses and all voted strategically for Split over 20. 

I have nothing but admiration for whatever heresthetician came up with this move. You, Sir or Madam, are deserving of some kind of award. I don't know what happened, but somebody managed to convince enough people in Parliament that the proposed rule change was actually more democratic for this kind of choice.

I've held off on blogging this one - I set it as a midterm exam question in my undergrad Public Choice class. Then things got busy. But here's the fun part.

Green MP Kevin Hague supported Keep It 18, as did I. But here's what he wrote after the vote:
In the wake of the parliamentary vote on alcohol purchase age there are some people (the ones I have seen are people who favoured 20) who are suggesting that the voting procedure used led to a perverse outcome.
I disagree completely. This is not a post about the merits or otherwise of the various options, but an argument that while the voting procedure was highly unusual, it produced a more democratic outcome than otherwise would have occurred, and should be considered more often. [emphasis added]
The first thing that I tell my public choice students about social choice is that if there's a Condorcet Winner, we generally consider it to be desirable that a social choice mechanism choose the Condorcet Winner. Here's Hague on what would have happened had we used the standard rules of order:
So recall that in this case the option that was in the Bill was the split age option, but that there were proposed amendments both to retain a uniform age of 18, or to raise it to a uniform 20. The ordinary House process would have seen first a vote on 18. If that had passed then the 20 proposal would have been ruled out of order. If it had failed we would have voted on the 20 option. If that had failed then the split option would have remained in the Bill.
Under the traditional voting method, what would have happened is this: the proposal for 18 would be put and fail. We would then have moved on to the 20 proposal, and this also would fail. This would leave the split age in the Bill – the option that was actually the least favoured by MPs.
I agree completely with Hague on the above. That's why I had $300 riding on it.
Instead first preferences were canvassed and the split age option, as the least favoured excluded. Then effectively those who had favoured the split age added their support to their second preference. Hence 68 votes for 18, 53 for 20.
The voting method used ensured that the result could command a majority in the House whereas the traditional method would not have done (except by excluding this whole part of the Bill I guess).
This is truly bizarre. Hague is saying:
  1. There was a Condorcet winner: Split would have won against both 18 and 20.* 
  2. The system we used, which ruled out the Condorcet winner on the first round, was more democratic.
Deciding what is more or less democratic is a bit of a mess because of all of the various problems in the social choice literature: we're usually trading off horrible features of various systems against each other. But it's awfully strange to prefer, on democratic grounds, that a Condorcet winner be suppressed!

I really really want to read the inside account of how they pulled this off. Think about everything that here was required:

  1. Flip from the normal rules of order and convince everybody that you're doing it for fairness reasons rather than to change the outcome.
  2. Do it late enough in the game that all the "Increase to 20" group don't have time to think through the game theory. If you do it early, somebody will point out to the ones too dim to figure it out on their own that they cut their own throats by supporting 20 over split at the first round, if their true preference ordering has 18 last. 20 then gets dropped in the first round and Split wins in the second. 
  3. Do it despite the government seeming to prefer the split age option, which lets them to be seen to be doing something on alcohol, where there's been a lot of public pressure. 
A proper account of this could make up a chapter in a revised version of William Riker's truly excellent little book, Heresthetics: The Art of Political Manipulation. The youth wings of some of the parties in the Keep It 18 movement seem to have completely gazzumuped their elders. Heck, I'd never even considered it possible that the rules of order could be a choice variable. This was a truly entrepreneurial act in the proper sense of the word. I have nothing but admiration for these kids. A beautiful application of heresthetics. 

Even worse, I doubt that anybody responsible for it would want to take credit for it as doing so might hinder future entrepreneurial efforts. Didn't the CIA award medals anonymously to operatives? Can we do that here?

David Farrar has all the data up on who voted which way in each round. I'll have to think of a fun honours project around this.

* You can build weird cases for non-single-peaked preferences if you think a lot of 20 supporters preferred 18 over Split, maybe so that, in their view, things would get so bad that we'd be able to increase the drinking age to 20 across the board (or a similar case for those who most preferred 18). And maybe then preferences could have cycled. But I don't buy it at all. And, more importantly, Hague doesn't buy it: he's saying there was a Condorcet winner.

1 comment:

  1. Great post, great anecdote. I wonder Hague would think about the reverse case, where the Condercet loser ends up winning?