A swing of 10.1% away from the Coalition was required for the Labor Party to win the 2017 State election. While the Labor Party enjoyed a 9.1% swing to its favour, the critical factor - a surprise to many - was an even larger swing of 15.9% away from the Liberal Party. The Coalition lost voters not just to Labor, but to One Nation and other minor parties, with Labor then preferenced higher than the Coalition, ultimately costing them the election. A key example of this is the seat of Murray-Wellington. Here Labor had a 7.9% swing towards them, but the Liberals had a massive 20.5% swing against, fuelled by the new candidates from One Nation and Shooters, Fishers, Farmers picking up 11.3% and 6.4% of the first preferences respectively.
The cartograms of the election results show that the metropolitan fringe previously held by Labor has extended well into the central suburbs, and the Coalition only has three “safe” seats remaining – Churchlands, Cottesloe and Vasse. Labor now has 24 “safe” seats, and with just 30 required to win, the Coalition has a tough job ahead of them come the next election.
Election results: http://www.abc.net.au/news/elections/wa-election-2017/
Marginal/Safe seat definitions: http://www.aec.gov.au/footer/Glossary.htm