Tuesday, September 15, 2009

Electorates and MMP

Over the weekend Labour went public with its idea to "improve" MMP by making it less proportional. One of the underlying assumptions here is that our electorates are "too large". But are they? Below is a table of FPP jurisdictions showing population, number of electorates in their lower house, and the effective quota:

CountryPopulationElectoratesPeople / electorate
Australian Federal government21,885,000150145,900
Canadian Federal33,778,000308109,669
New South Wales7,017,0009375,452
New Zealand4,315,0007061,643
British Colombia4,420,0008552,000
Western Australia2,163,0005936,661
South Australia1,598,0004734,000

As can be seen, New Zealand appears in the middle of the table; we're certainly not wildly out of step with the rest of the Westminster tradition here, and our seats are smaller than any of the comparable national legislatures (the comparison is even better when you remember that those list MPs don't just sit around in Wellington with paper bags over their heads, but adopt electorates and do constituency work; counting them puts us well into the bottom half of the table, with a mere 35,369 per representative).

The problem isn't one of population. Rather it is one of geographic size, caused by our low population density. The classic example here is the West Coast - Tasman electorate [PDF], which covers about a quarter of the South Island because nobody bloody lives there. Such geographically large electorates reduce access to MPs - something which NZ is good at (most of the Maori seats have similar problems; Te Tai Tonga [PDF] covers the whole South Island as well as Wellington and the Hutt Valley). All other things being equal, smaller electorates would be better.

The problem is that all other things aren't equal. Simply reapportioning the balance of electorate and list seats within the 120 seat cap undermines proportionality, leading to regular overhangs in favour of the largest party. If we want geographically smaller electorates, we really only have two options:

  • Increase the size of Parliament. The optimum size - the cube root of population - is about 161 members now anyway. This will be unpopular, but if you didn't want more politicians, you shouldn't have been having kids.
  • Allow some electorates (either a limited number, or defined geographically) to exceed the existing 5% tolerance (so e.g. allowing a small number in the South Island to be 10% or even 15% out). This undermines the principle that everyone's vote should count equally, but only on the electorate vote. And in an MMP system, where the overall shape of Parliament is proportional to the list vote, that doesn't actually pose too much of a problem and is extremely unlikely to affect the outcome (I should note here that the Royal Commission on the Electoral System recommended a 10% tolerance for exactly this reason).
Either solution would require a referendum or a supermajority, as both the number of electorates (or rather, the number in the South Island, from which all else is derived) and the 5% tolerance are entrenched provisions.

And either way, the longer term solution is to allow Parliament to grow with the electorates, by removing the hardcoded size of 120 members and instead replacing it with the number of electorates plus a hardcoded number of list seats. That should insulate us from further problems for another 50 years or so.