The Two-Party Preferred Vote in O'Connor

The counting has been finished and the AEC reports that the two-party preferred (TPP) result in the seat of O'Connor is

Australian Labor Party

22,029 votes

27.00 %

Liberal/National Coalition

59,555 votes

73.00%

The margin is 37,526 votes.

However, this is not quite correct as it is presented.

The AEC actually distributed all the 81,584 formal votes in O'Connor into two piles: those that preferred Ian Bishop(ALP) over Tony Crook(Nat) and those that preferred Crook over Bishop.

The problem with this is that Tony Crook, along with other WA National Party candidates campaigned on a platform which included the intention of not joining any Liberal National Coalition. Mr Crook reaffirmed that after the election. Mr Crook has not joined any such Coalition since being elected (and it it is not clear there is any formal Coalition agreement now
anyway).

There was actually a sitting Coalition member for this seat, Wilson Tuckey, who was running for re-election and so Mr Crook was clearly not running as Coalition candidate.

It would thus seem more correct for the AEC to have distributed the votes in O'Connor on a TPP basis as Bishop versus Tuckey. This is what happens in other seats where there are Independents or Minor Party candidates in the final two positions.

What difference would that have made to the final figures. We can not tell exactly but below I attempt and estimate.

There are 9 candidates with first prefs as follows:
HUNTLEY, Andy: The Greens: 7232
ROBINSON, Jean: Citizens Electoral Council: 375
TUCKEY, Wilson: Liberal: 31294
SCALLAN, Pat: Family First: 1164
YOUNG, Jacky: Christian Democratic Party: 2221
CROOK, Tony: The Nationals: 23538
STOKES, Geoffrey: Independent: 1298
BISHOP, Ian: Australian Labor Party: 13962
SMITHSON, Neil Ramsay: Independent: 500

The TPP candidates are as follows:
BISHOP, Ian
CROOK, Tony

We can estimate how many votes get distributed to the two TPP candidates.
Best match of TPP booth results is with following preference flows:
From HUNTLEY, Andy to BISHOP, Ian: 79.74% which amounts to 5767 votes.
From ROBINSON, Jean to BISHOP, Ian: 52.88% which amounts to 198 votes.
From TUCKEY, Wilson to BISHOP, Ian: 1.81% which amounts to 566 votes.
From SCALLAN, Pat to BISHOP, Ian: 41.14% which amounts to 479 votes.
From YOUNG, Jacky to BISHOP, Ian: 5.06% which amounts to 112 votes.
From CROOK, Tony to BISHOP, Ian: 0% which amounts to 0 votes.
From STOKES, Geoffrey to BISHOP, Ian: 36.93% which amounts to 479 votes.
From BISHOP, Ian to BISHOP, Ian: 100% which amounts to 13962 votes.
From SMITHSON, Neil Ramsay to BISHOP, Ian: 93.11% which amounts to 466 votes.

We also have a two-candidate count in O'Connor which was distributed on a Tuckey versus Crook basis. The result was

TUCKEY, Wilson

Liberal

37,891

46.44 %

CROOK, Tony

The Nationals

43,693

53.56 %

The estimated preference flows are:
Best match of TCP booth results is with following preference flows:
From HUNTLEY, Andy to CROOK, Tony: 70.17%
From ROBINSON, Jean to CROOK, Tony: 0.58%
From TUCKEY, Wilson to CROOK, Tony: 0%
From SCALLAN, Pat to CROOK, Tony: 29.43%
From YOUNG, Jacky to CROOK, Tony: 26.97%
From CROOK, Tony to CROOK, Tony: 100%
From STOKES, Geoffrey to CROOK, Tony: 10.68%
From BISHOP, Ian to CROOK, Tony: 100%
From SMITHSON, Neil Ramsay to CROOK, Tony: 7%

So my estimates of the preference distribution between Tuckey and Bishop would be:

From HUNTLEY, Andy to BISHOP, Ian: 79.74% which amounts to 5767 votes.
From ROBINSON, Jean to BISHOP, Ian: 52.88% which amounts to 198 votes.
From TUCKEY, Wilson to BISHOP, Ian: 0% which amounts to 0 votes.
From SCALLAN, Pat to BISHOP, Ian: 41.14% which amounts to 479 votes.
From YOUNG, Jacky to BISHOP, Ian: 5.06% which amounts to 112 votes.
From CROOK, Tony to BISHOP, Ian: 20% which amounts to 4708 votes.
From STOKES, Geoffrey to BISHOP, Ian: 36.93% which amounts to 479 votes.
From BISHOP, Ian to BISHOP, Ian: 100% which amounts to 13962 votes.
From SMITHSON, Neil Ramsay to BISHOP, Ian: 93.11% which amounts to 466 votes.

The main figure here is the 20% flow from Crook to Bishop (over Tuckey) in keeping with the sort of flow measured in O'Connor in 2007.

The end result is:
Bishop 26,171 or 32.08%
Tuckey 55,413 or 67.92%

The margin is 29,242 votes.

That is better margin for the ALP and would have given them an extra 8,284 votes in their National TPP win.

The final National Tally would have then been
ALP 50.19% versus LNP 49.81%