Are we there yet?

Is there where the betting market is likely to settle following the elevation of Malcolm Turnbull to the Liberal leadership?

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-29	Betfair	1.29	3.85	74.902724
2015-09-29	CrownBet	1.28	3.65	74.036511
2015-09-29	Ladbrokes	1.25	3.80	75.247525
2015-09-29	Luxbet	1.28	3.65	74.036511
2015-09-29	Sportsbet	1.25	4.00	76.190476
2015-09-29	TABtouch	1.21	4.25	77.838828
2015-09-29	William Hill	1.22	4.25	77.696527

Another day, another shortening in Coalition odds

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-27	Betfair	1.24	4.13	76.908752
2015-09-27	CrownBet	1.28	3.65	74.036511
2015-09-27	Ladbrokes	1.25	3.80	75.247525
2015-09-27	Luxbet	1.28	3.65	74.036511
2015-09-27	Sportsbet	1.25	4.00	76.190476
2015-09-27	TABtouch	1.21	4.25	77.838828
2015-09-27	William Hill	1.22	4.25	77.696527

Odds on a Shorten premiership lengthen

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-25	Betfair	1.21	3.61	74.896266
2015-09-25	CrownBet	1.33	3.25	70.960699
2015-09-25	Ladbrokes	1.30	3.30	71.739130
2015-09-25	Luxbet	1.28	3.65	74.036511
2015-09-25	Sportsbet	1.28	3.75	74.552684
2015-09-25	TABtouch	1.21	4.25	77.838828
2015-09-25	William Hill	1.22	4.25	77.696527

Honeymoon continues

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-24	Betfair	1.29	3.47	72.899160
2015-09-24	CrownBet	1.33	3.25	70.960699
2015-09-24	Ladbrokes	1.30	3.30	71.739130
2015-09-24	Luxbet	1.28	3.65	74.036511
2015-09-24	Sportsbet	1.28	3.75	74.552684
2015-09-24	TABtouch	1.27	3.65	74.186992
2015-09-24	William Hill	1.28	3.65	74.036511

Updates

Today we have two new polls:

• the first Newspoll of the Turnbull season has it at 51 to 49 in the Coalition's favour. This represents a five point movement to the Coalition over the previous Newspoll and the previous prime minister.
• the first Morgan poll of the season has it at 53.5 to 46.5 in the Coalition's favour (with preferences distributed according to the previous election). This represents a ten point movement to the Coalition over the previous Morgan poll. 

I had debated whether the treat the Morgan Poll as an outlier, and exclude it from the aggregation. In the end I decided it would be better practice to keep it in. But I will review this decision as further polls come to hand. With the Morgan poll, the aggregation stands at 51.3 in the Coalition's favour (to Labor's 48.7).

The anchored model gives the Coalition a further 0.7 percentage points (52.0 per cent).

Betting markets

The past 24 hours have seen some movement towards the Coalition from betfair and ladbrokes. 

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-22	Betfair	1.27	3.47	73.206751
2015-09-22	CrownBet	1.40	2.75	66.265060
2015-09-22	Ladbrokes	1.30	3.30	71.739130
2015-09-22	Luxbet	1.40	2.85	67.058824
2015-09-22	Sportsbet	1.28	3.75	74.552684
2015-09-22	TABtouch	1.27	3.65	74.186992
2015-09-22	William Hill	1.28	3.65	74.036511

Update

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-21	Betfair	1.36	3.00	68.807339
2015-09-21	CrownBet	1.40	2.75	66.265060
2015-09-21	Ladbrokes	1.40	2.80	66.666667
2015-09-21	Luxbet	1.40	2.85	67.058824
2015-09-21	Sportsbet	1.28	3.75	74.552684
2015-09-21	TABtouch	1.27	3.65	74.186992
2015-09-21	William Hill	1.28	3.65	74.036511

Mixed signals

This morning sportsbet has increased the odds of a Coalition win, while betfair has decreased them.

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-20	Betfair	1.35	2.80	67.469880
2015-09-20	CrownBet	1.40	2.75	66.265060
2015-09-20	Ladbrokes	1.40	2.80	66.666667
2015-09-20	Luxbet	1.40	2.85	67.058824
2015-09-20	Sportsbet	1.28	3.75	74.552684
2015-09-20	TABtouch	1.26	3.75	74.850299
2015-09-20	William Hill	1.27	3.75	74.701195

Update

Betting markets

What a week. Today the betting market has moved further in Turnbull's favour, solely off the back of activity at sportsbet.

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-19	Betfair	1.35	3.14	69.933185
2015-09-19	CrownBet	1.40	2.75	66.265060
2015-09-19	Ladbrokes	1.40	2.80	66.666667
2015-09-19	Luxbet	1.40	2.85	67.058824
2015-09-19	Sportsbet	1.30	3.50	72.916667
2015-09-19	TABtouch	1.26	3.75	74.850299
2015-09-19	William Hill	1.27	3.75	74.701195

Anchored TPP model

I have extended the discontinuity approach to my anchored two-party-preferred model. Rather than assume that collectively polling houses are unbiased, this model anchors the estimate of house effects to the election outcome in 2013. Arguably an anchored poll aggregation based yields a more accurate estimation of the actual population-wide voting intention. I say arguably, because, there are many caveats and assumptions for this to be the case. The results are as follows:

The immediate polling benefits of change

While it is premature to make these comparisons, this anchored model had the pre-spill Abbott polling at 46.4 per cent and the immediate benefit of the leadership change at 4.6 percentage points. The unanchored model (in which house effects are forced to sum to zero) had the pre-spill Abbott polling at 46.0 per cent and an immediate benefit of the leadership change at 4.3 percentage points. Side-by-side, these models estimate population voting intention as follows:

Update

This morning the Murdoch tabloids have a new poll from Galaxy (the first since the Budget) at 51-49 in the Coalition's favour. This is a three point movement in the Coalition's favour since the previous Galaxy poll. The impact of this second poll on the post-Abbott aggregation is minimal: 50.2 to 49.8 per cent in the Coalition's favour.

The betting market appears to have settled.

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-18	Betfair	1.35	3.14	69.933185
2015-09-18	CrownBet	1.40	2.75	66.265060
2015-09-18	Ladbrokes	1.40	2.80	66.666667
2015-09-18	Luxbet	1.40	2.85	67.058824
2015-09-18	Sportsbet	1.40	3.00	68.181818
2015-09-18	TABtouch	1.26	3.75	74.850299
2015-09-18	William Hill	1.27	3.75	74.701195

75 per cent probability of a Coalition win?

UK bookmaker William Hill (which in Australia includes the Centrebet and Tom Waterhouse brands) has the odds out to $1.27 for the Coalition and $3.75 for Labor. That's a Coalition win probability of 75 per cent in round terms. If you want better returning odds for the Coalition, you can look at Crownbet, Ladbrokes, Luxbet, or Sportsbet for $1.40.

It sounds like William Hill took some serious money on the Coalition which they need to balance on their books. Over coming days it will be interesting to see whether William Hill eases back or the other houses push on to join William Hill.

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-17	Betfair	1.35	3.14	69.933185
2015-09-17	CrownBet	1.40	2.75	66.265060
2015-09-17	Ladbrokes	1.40	2.80	66.666667
2015-09-17	Luxbet	1.40	2.85	67.058824
2015-09-17	Sportsbet	1.40	2.90	67.441860
2015-09-17	TABtouch	1.26	3.75	74.850299
2015-09-17	William Hill	1.27	3.75	74.701195

First post-Abbott aggregation (not to be taken too seriously)

Today's ReachTEL was conducted on Tuesday this week, the day after the Turnbull ascension. The result was 50-50, which is a three point move in the Coalition's direction over the previous ReachTEL poll.

It will take a full cycle of polling before we have a sense of the immediate impact of the change in Liberal leadership. So I would not read too much into today's result.

Ignoring my own advice, I thought it would interesting to drop the ReachTEl poll into the usual aggregation. This is the one where the house effects sum to zero. I made an adjustment to the polling model to allow for a discontinuity in the temporal element of the model for the leadership change on 14 September 2015.  (I used a similar discontinuity technique in 2013 when Rudd replaced Gillard).

The result, which should be consumed with more than the usual pinch of salt, is a tie. This is unsurprising given the house effect the model applies to the one-and-only post discontinuity poll.

For the nerds among you, the discontinuity model I used follows:

model {
    ## -- observational model
    for(poll in 1:n_polls) { # for each observed poll result ...
        yhat[poll] <- houseEffect[house[poll]] + hidden_voting_intention[day[poll]]
        y[poll] ~ dnorm(yhat[poll], samplePrecision[poll]) # distribution
    }

    ## -- temporal model - with one discontinuity
    hidden_voting_intention[1] ~ dunif(0.3, 0.7)
    for(i in 2:(discontinuity-1)) { 
        hidden_voting_intention[i] ~ dnorm(hidden_voting_intention[i-1], walkPrecision)
    }
    hidden_voting_intention[discontinuity] ~ dnorm(hidden_voting_intention[discontinuity-1]+discontinuityValue, walkPrecision)
    for (j in (discontinuity+1):n_span) {
        hidden_voting_intention[j] ~ dnorm(hidden_voting_intention[j-1], walkPrecision)
    }
    sigmaWalk ~ dunif(0, 0.01)
    walkPrecision <- pow(sigmaWalk, -2)
    discontinuityValue ~ dunif(-0.1, 0.1) ## contextually uninformative prior

    ## -- house effects model
    for(i in 2:n_houses) { # for each polling house, except the first ...
        houseEffect[i] ~ dunif(-0.15, 0.15)
    }
    houseEffect[1] <- -sum( houseEffect[2:n_houses] )
}

And the next day

Overall, the win probabilities further improve for the Coalition.

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-16	Betfair	1.35	2.95	68.604651
2015-09-16	CrownBet	1.40	2.75	66.265060
2015-09-16	Ladbrokes	1.40	2.80	66.666667
2015-09-16	Luxbet	1.40	2.85	67.058824
2015-09-16	Sportsbet	1.40	2.90	67.441860
2015-09-16	TABtouch	1.33	3.20	70.640177
2015-09-16	William Hill	1.34	3.20	70.484581

For today's charts, I have gone back to the morning readings for Monday (my usual practice). I have also left the charts blank for the days that a betting house was not issuing odds. Crownbet did not have odds for much of last week and Luxbet did not have odds on Monday morning.

The morning after

This morning (at a little past 7am Australian Eastern Standard Time) the markets had further firmed for the Coalition on 9pm last night (prior to the leadership vote within the Liberal Party room).

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-15	Betfair	1.45	2.95	67.045455
2015-09-15	CrownBet	1.40	2.75	66.265060
2015-09-15	Ladbrokes	1.40	2.80	66.666667
2015-09-15	Luxbet	1.40	2.85	67.058824
2015-09-15	Sportsbet	1.40	2.90	67.441860
2015-09-15	TABtouch	1.39	2.90	67.599068
2015-09-15	William Hill	1.40	2.90	67.441860

Noting that the reading for 14 September is an 9.05pm evening reading, rather than a morning reading.

Pre-vote Betting Market favours the Coaltiion

At 9.05pm, before the Liberals gather to choose between Abbott and Turnbull, the Betting market believes the challenge augurs well for the Coalition.

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-14	Betfair	1.43	2.48	63.427110
2015-09-14	CrownBet	1.55	2.45	61.250000
2015-09-14	Ladbrokes	1.50	2.45	62.025316
2015-09-14	Luxbet	1.53	2.40	61.068702
2015-09-14	Sportsbet	1.50	2.65	63.855422
2015-09-14	TABtouch	1.52	2.48	62.000000
2015-09-14	William Hill	1.53	2.50	62.034739

Interpretation: the betting market expects a leadership change (either now or in the near future), and this will be good for the Coalition's electoral fortunes. Only a few minutes to go to see if the markets are correct.

Betting markets

Not a lot to report this week.

Crownbet closed its book on the Federal election. I have not been able to collect odds since Tuesday this week.

The best odds for the Coalition can be found at Sportsbet ($1.73). The best odds for Labor can be found at Betfair ($2.25 adjusted).

	House	Coalition Odds ($)	Labor Odds ($)	Coalition Win Probability (%)
2015-09-11	Ladbrokes	1.70	2.10	55.263158
2015-09-11	Luxbet	1.66	2.15	56.430446
2015-09-11	Sportsbet	1.73	2.15	55.412371
2015-09-11	TABtouch	1.71	2.09	55.000000
2015-09-11	William Hill	1.72	2.10	54.973822
2015-09-11	Betfair	1.66	2.25	57.544757