Continuing on from Pollycide 1 where we used various weights derived from the quarterly Newspoll data to give us some experimental 2 party preferred results to show us the type of seats that would have likely changed hands in a July election, and following on from Pollycide 2 where we then used some linear programming to fit that seat pattern into the actual swings observed in the quarterly Newspoll – we now take it all back to basics, because sometimes the simple things in life are… well, simple and effective.

I noticed some dubious reaction to how these seat swings are possible (well, I noticed them once I managed to get past all the ALP supporters throwing confetti everywhere), so I thought we’d get back to the basics to show that I’m not making this up.

To do this, we’ll use the Newspoll quarterly data from March-June 2007, and compare that to the actual 2004 Election results to give us the TPP swings for each state. We can then compare these swings using the State Pendulums and we’ll get a basic, but realistic assessment of the seats that would have been likely to change hands were an election held in July.

To start off with, let’s take a squiz at the 2004 Election TPP results and the Q2 Newspoll data to find the state swings:

2004 Election

TOTAL

NSW

VIC

QLD

SA

WA

Coalition

52.8

51.2

51

57.1

54.4

55.4

ALP

47.2

48.8

49

42.9

45.6

44.6

2007Q2 Newspoll

 

 

 

 

 

 

Coalition

43

39

42

46

44

50

ALP

57

61

58

54

56

50

ALP Swing

9.8

12.2

9

11.1

10.4

5.4

Coalition Swing

-9.8

-12.2

-9

-11.1

-10.4

-5.4

That entry “ALP Swing” is the one you want to pay attention to here.

Now comparing these swings to these graphs we get the following numbers of seats changing hand for each state:

NSW: ALP gain of 17

Vic: ALP gain of 8

Qld: ALP gain of 14

SA: ALP gain of 5

WA: ALP gain of 2.

That’s a total gain of 46 seats.

However, lets look at Tassie and the NT where Solomon would fall with a 2.9% swing, Bass would fall with a 2.7% swing and Braddon would fall with a 1.2% swing.

With a national swing of 9.8% – it’s a safe bet that those three seats would all fall as well, giving us a total ALP gain of 49 seats.

The Pollycide 2 numbers and the seat list suggested 47 seats would have been lost in NSW, Vic, Qld, SA and WA. Remember, that seat list was derived from Pollycide 1, and adjusted to fit within the State based swings – although it was more luck than skill that the numbers matched up just about perfectly as it could have been 3 or 4 seats in either direction due to the nature of the maths and where I chose to draw the line in terms of leaving some unaccounted for swing in NSW.

So, from Pollycide Part 1 we can see the types of seats that would have been lost in a July election, from Pollycide Part 2 can see a good estimation of which seats and the margins involved were an election held in July, and with Pollycide 3 we have verified those numbers.

That’s the good news for the government. Yes, the GOOD news.

The bad news is that the above verification based on the state Newspoll swing estimations doesn’t account for the composition of marginal and safe seats. The ALP are only swinging 4.1% toward them in their safe seats, the marginals are swinging 9.3% toward the ALP and the safe government seats are swinging 14.6% toward the ALP for an overall national swing of 9.8%.

As there was residual swing left from the seat calculations in Pollycide 2 (which is where we tried to account for the marginal and safe seat movements), that means that the swings actually underestimate the actual seat numbers that would have been lost.

By how much? – up to 10-15 seats depending on where the residual swing fell.

So what we can feel fairly safe saying is that were an election held recently, according to 3 months worth of polling by Newspoll, the ALP would have gained 49 seats as a minimum, somewhere around 55-60 seats as a more likely possibility and a high of somewhere around 65.

That really is a Pollycide.

If you want to check out the details of any of the seats mentioned in the Pollycide series, Adam Carrs magnificent psephology site has a smorgasbord of info on all of them in his 2007 Federal Election Guide.

Small Update – I over counted NSW by 1 as a result of putting a seat in the wrong spot in my NSW swing graph.Its all fixed up now with NSW giving 17 seats rather than 18.

Thanks to the dozen or so people that pointed it out – nothing get’s past you folks.

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