South Australian redistribution: draft maps released

Late last week the Electoral District Boundaries Commission of South Australia released draft boundaries for the next South Australian state election in March 2014.

Antony Green has covered the changes and their significance in more depth, including margins for every seat and a description of each seat’s change. You can also see the maps at the ECSA website.

South Australian electoral law requires a redistribution following every election. In addition, SA electoral law requires that electoral boundaries be ‘fair’, which in the past has been interpreted as drawing electoral boundaries that would result in the party that wins a majority of the two-party-preferred vote winning a majority of seats.

Despite this law, the last election saw the ALP win a majority of seats while the Liberal Party won a solid majority of the vote (51.6% of the 2PP vote). This was largely achieved due to the ALP suffering massive swings in their safest seats while largely holding their ground in their marginal seats.

It was expected that this would require a significant redrawing of the electoral map to give the Liberal Party a notional majority of seats. However, the Commission instead decided to make relatively minor changes. Not a single seat held by the major parties has changed hands on the boundaries. As Antony Green has said:

The Commission’s justification is that it has decided the boundaries at the 2010 election were fundamentally fair. However, the differential nature of the swing denied the Liberal Party a majority. The Commission has decided the differential swing was a campaign factor, not one caused by an unfairness in the boundaries drawn in 2007.

It is yet to be seen if the final boundaries will produce a more significant change. Even with boundaries that preserve the ALP’s majority, it is likely the ALP government will suffer a significant swing in 2014, making this redistribution largely irrelevant.

You can download my Google Earth map of the draft 2014 boundaries along with the previous four seats of maps at the maps page. You can also download a time series map that shows the changes in SA electoral boundaries since 1997.

2010 South Australian electoral boundaries, showing the Adelaide area.

Draft 2014 South Australian electoral boundaries, showing the Adelaide area.