I have been meaning to write a post about the impending determination and possible solutions to the likely merger of the NT’s two federal seats. Antony Green put together a long and interesting piece yesterday explaining how the current formula short-changes the territories, and suggests an alternative formula which would produce a better result, as well as some background on where our current system comes from. I’m going to quickly run through this issue for those who don’t have time to dive in deep.

I wrote about this likely outcome in August last year. It looks likely that Victoria will gain a 39th seat, Western Australia will lose its 16th seat, and that the Northern Territory will revert to just one electorate, after gaining a second seat at the 2001 election.

The current formula determines a national quota dividing the total population of the six states by twice the number of state senators (144). This formula is the default specified in the Australian constitution (although the parliament does have some room to move by changing the formula). The same formula is used to allocate ACT and NT seats, but this is not fixed in the constitution and could be changed.

Labor senator Malarndirri McCarthy has put forward legislation that would set a minimum number of electorates for the territory at two, thus averting the seat loss. But Antony has proposed another change which would slightly improve representation for the territories without setting a hard floor.

This formula can be problematic when a territory has a small number of electorates. There is a massive change in the average population per seat when you jump from one to two seat, or from two to three. The average population per seat will be much higher if you have 1.4 or 2.4 quotas of population than if you have, say, 40.4 quotas.

Antony recommends a formula called Dean’s formula.

In short, it allocates the number of seats to each jurisdiction which would bring the average population per seat as close as possible to the national quota.

In the case of the NT, this means that anything more than 1.33 quotas of population would qualify for two seats. A third seat would be allocated if a territory had more than 2.4 quotas. This formula gets pretty close to the current formula once a jurisdiction is allocated more than a few seats. It’s actually simpler than I thought it would be, and I think it could be a good solution.