Why don’t we have 152 seats in the House of Representatives?

Earlier today I was trying to figure out why the House of Representatives only has 150 seats instead of 152, in light of Section 24 of the Constitution. It states that the number of seats in the House of Representatives should be, nearly as practicable, twice the number of Senators. Logically, you would think it means 76 x 2 = 152

It’s clarified in the Commonwealth Electoral Act with a formula provided under Section 48 to determine how many House of Representatives seats there are and where each seat is allocated.

To get the number of seats, a state/territory is entitled to, you need to first determine the quota:

National population (excluding the population of the territories) / 2 x number of Senators from the states

So the numbers are 22,155.4 – (354.9 + 227.7) [equals 21,572.2] / 144

It comes up with a quota of approximately 149.81

Then each states/territories population is divided into the quota and rounded to the nearest 0.5 to come up with a seat allocation.

Using the latest population data from the ABS (December 2009 quarter), I did a quick calculation of entitlements. Unfortunately, it looks like the ACT is still a fair way off getting a third seat on 2.36.

Of interest is that if the Senate was expanded to 14 per state, by amending the Representation Act, with 7 members elected at each election, the ACT would get a third seat with the House of Representatives expanded to 175. The new quota would be approximately 128.41.

The calculations are here for those interested

N.B. There’s also some interesting provisions regarding Senators from the ACT and NT in the Electoral Act such as vacancies being filled by the Legislative Assembly and needing to get to at least 6 MPs to get an additional Senator.