South Australian state redistribution update


This is a quick blog post about a story that I’ve missed up until now.

As they do every four years, the South Australian electoral boundaries are currently in the process of being redistributed. The draft boundaries are due to be released at 11am Adelaide time this morning. This follows a round of submissions earlier this year, which largely went under the radar due to the federal election.

South Australia conducts redistributions after every election. Unlike other jurisdictions around Australia, the boundaries commission is required to ensure that the result is “fair” – ie. that a majority of the two-party-preferred vote gives a majority of seats. I’m on the record as thinking that this is an impossible task. By definition a system of single-member electorates are not fair, it can’t handle multiparty politics, and is always undone by different swings across the state.

The 2010 election saw Labor hold on to its majority despite losing a majority of the two-party-preferred vote, despite the best efforts to draw boundaries which wouldn’t produce this result. After this election, the boundaries commission decided that the boundaries were not unfair and didn’t attempt to undertake major redrawing of the boundaries to undo Labor’s new advantage.

The following map shows how much each seat diverges from the average quota as of 2016. Seats marked in red are above average, those in blue below average. Those in pale yellow are within a range of 1% either above or below. Those in a darker colour are 5% above or below average.

Seats must fall within 10% of the average. Technically only two seats fall outside this band: Port Adelaide is over 10% above average, and the remote north-western seat of Giles is over 10% below average.

In practice a lot more seats will be redrawn. On a regional basis, seats in the northern suburbs of Adelaide are above average. There are four seats north of the Adelaide city centre which are more than 5% above quota. The nine seats at the northern end of Adelaide are collectively 17.6% above quota, while the fifteen seats in central Adelaide are 7.4% above quota, and the southern Adelaide seats are mostly sitting around the quota.

The five seats in northern South Australia are collectively 22.7% below their fifth quota. This suggests that we should expect one of these rural seats to be pulled further into the northern fringe of Adelaide, to absorb the surplus population in Adelaide. We’ll find out soon enough.

I should note that I’m not planning to immediately drop everything to construct a map of the new draft SA boundaries, as I am hoping to produce a guide to some of the biggest councils up for election in New South Wales in September. I’ll return to produce this map later in the year once other elections no longer monopolise my time.

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  1. Thanks Ben, you are doing a great job! If you ever get time, could you please do an article about the New Zealand MMP system?

  2. Report with draft proposal here:

    Controversies include:
    – whether in applying the fairness criterion, an independent member in a rural seat (based however on a strongly labour industrial town, of which he was previously mayor) counts toward the Liberals or Labor. He's a member of the Labor government
    – the extent to which the commission needs to aim for equal electorates.

    The report proposes renaming a half dozen seats, and would make a dozen or so (from 47) highly marginal, with a dozen more within arguable "reach" depending on how the election goes. Creates a series of quite elongated seats that breach the suburban/rural boundary, principally to accmmodate the continuation of 4 seats abutting Spencer Gulf, which features 4 urban centres (Port Lincoln, Whyalla, Port Augusta and Port Pirie) of widely different interests and population, all of which are well below quota for a separate seat.

  3. It’s a tough job re-stributing South Australia with many factors working against it, even before the potential X factor comes to town
    – High concentration of liberal votes in the country and eastern suburbs. The electoral commission appear disinclined to create wagon wheel electorates
    – The liberals are prone to members jumping to the cross bench.
    – Conservative / liberal Independents have a tendency to join Labor ministry
    – Labor seem exceptionally good at campaigning in marginal seats and or Liberals are really bad at campaigning, leading to wildly ununiform swings


  4. Imaginative

    Look at Morialta, Newland, Mawson and Bragg – if those aren’t incipient wagonwheel electorates I’m not sure what a different re-distribution could look like.

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