Senate Predictions 2010
Russell Degnan

Somewhat belatedly, I thought it would be worth revisiting the Senate prediction method used in 2007. Unfortunately, it wasn't as effective as hoped, as can be seen by the graph below.

While 1996 saw a strong movement away from the sitting government, and towards minor parties, the 2007 election was closer to 1983. Strongly towards Labor directly from the Liberals, rather than the collapse of the government vote.

Thus, while the swings were pretty close (although consistently overshooting), the minor party swing was the reverse of that expected, except in South Australia (where the Xenophon effect had been extensively polled) and Tasmania (which is seeing consistent growth in the Green vote).

This election promises to be more typical, following the patterns set in 1984 and 1998 where first term governments suffered heavy swings without any increase in the opposition's primary senate vote.

Tracing the HoR polls, as before, onto primary vote percentages, and the expected minor swings gives the following predictive graph.

Using Antony Green's senate calculator produces the following in each state:

South Australia
Unusual, in that the lack of a Xenophon votes means the minor parties will probably go backwards, to roughly in line with historic trends. Two seats are up for grabs, leaving the three main parties in a race. The Greens need over 11-12% of the vote which is puts them on the knife-edge, given recent polls. The Liberal easily ride to 5th, but Democrat preferences will go to Labor, so the Greens lot depends on whether their vote has a post-collapse anti-major electoral rebound, but also, by how much the Liberals pass their third quota, as the Greens get almost nothing from anyone until they are out.
Liberals 3, Labor 2(3), Greens 1(0)

Western Australia
A straight-forward count, giving the 6th sport to the Greens easily, the CDP makes a late run as it scoops up votes from all-comers, but the Labor party will tip the Greens over the line, without making a serious challenge for the sixth spot themselves.
Liberals 3, Labor 2, Greens 1

A straight forward vote, Liberal pick up an easy 3 from the right wing vote. Given the expected swing, Labor will never challenge for the 6th, put use their preferences to put the Greens over the line against Family First, who should slide into second.
Liberals 3, Labor 2, Greens 1

Greens easily take 5th, as they have Democrats preferences if they fail to make quote themselves. Any pro-Gillard swing will put Labor very close to a third quota, but they get almost no preferences above the Liberals, so the Liberals need around a 37% primary vote to crawl over the line. If the Liberal vote goes further south, Steven Fielding will need both around 4% himself and a weaker than expected Green/ALP vote to take advantage of the DLP's pre-ALP ballot position and crawl back into Parliament. Unlikely.
Liberals 2, Labor 3, Greens 1

New South WalesInteresting count. Labor's likely vote collapse means they need both the Green/Democrats vote to stay below a quota and their own vote to stay above 36% to come second above the CDP. If they succeed, right-wing votes will tip them into a third quota, otherwise the Greens will carry Labor preferences home: they need around 11.5% to win, right where they are currently polling.
Liberals 3, Labor 2(3), Greens 1(0)

Who knows what is going on here. Most likely outcome is actually 6 quotas filled and no distribution. But there is an outside chance that both Labor and Liberal will fail to fill their 2nd/3rd quotas, leaving the Greens or Liberals a chance of taking the 6th seat if their vote explodes upwards.
Liberals 2, Labor 3, Greens 1

Australia Capital Territory
The Greens always hope to win this one, but they need a strong Labor vote to keep the Liberals under the quota of 33%. That's unlikely amongst a big NSW anti-Labor swing, and almost impossible with Democrats preferences heading towards the Liberals, though a pro-Labor, anti-Liberal population turnover means it can't be ruled out completely.
Liberals 1, Labor 1, Greens 0

Northern Territory
Forget it.
Liberals 1, Labor 1, Greens 0

By the numbers:
Liberals 18, Labor 16(18), Greens 6(4)

Liberals 16, Labor 16, Greens 3, Xenophon 1

In total:
Liberals 34, Labor 32(34), Greens 9(7), Xenophon 1

Sterner Matters 21st August, 2010 19:30:03   [#]