All the polls suggest that this election is very close to a tie but that may not be enough for Labor to win.
National polls are suggesting a very close race, with most polls putting the gap between the parties at no more than 2%. The Guardian poll of polls has the Coalition on 50.71% after preferences.
While either side has a chance of winning the election, the Coalition is more likely to win if the national two-party-preferred vote is effectively a tie. Labor, on the other hand, would need to significantly outpoll the Coalition to be likely to win a majority. This is in part because the personal vote of first-term MPs will give the Coalition a boost in many of its marginal seats.
In 2013, Tony Abbott’s Coalition won 53.5% of the vote after preferences were distributed. If there were a uniform swing of 3.5% in every electorate from the Coalition to Labor, the Coalition would win 75 seats and Labor 71. But thanks to a phenomenon known as “sophomore surge”, the Coalition would likely win more than 75 seats if they won exactly half of the two-party-preferred vote.
A majority of voters usually vote based on broad national trends – most seats within a state tend to swing in the same direction. But each MP also has a personal vote that can give them a boost above their party’s general support base.
MPs develop personal votes for a variety of reasons. Sitting MPs are prominent personalities in their community. They appear regularly in local media and sometimes in the national media, they attend events and they will do a variety of campaigning outside of election time. The same is not normally true of their opponents.
Federal MPs also benefit from a tremendous financial advantage over their opponents. The federal parliament employs a number of staff for each MP, along with a well-resourced office. Federal MPs also have large budgets for communicating with their constituents. Federal MPs also play a role in providing government assistance to constituents.
If someone has represented their electorate for a long time, you can assume that their personal vote is factored in to their electorate margin. But if there is a change in the person who represents an area, this can lead to what is sometimes called a “sophomore surge”.
A first-term MP is expected to have some kind of personal vote after representing their electorate for three years. That personal vote didn’t exist at the previous election, so it wasn’t factored into the margin. Thus, you should expect a first-term MP to do slightly better than the national or statewide trend would suggest.
This effect is more substantial if they defeated an MP of the opposing party at the previous election. The effect isn’t quite as strong when the sitting MP (of either party) had retired at the last election.
Personal votes can also be a factor when a sitting MP retires. With the party no longer benefiting from that candidate’s personal vote, that seat will often see a less favourable swing for the party holding the seat.
Electoral analyst Peter Brent (who has written a lot about the sophomore surge) estimates that an MP’s personal vote can be worth around 1-2%.
Sophomore surge is most evident when first-term governments are seeking a second term. If a government is in its first term, most of its marginal seats will be held by new MPs who are building a new personal vote. If a sophomore surge happens in a series of key marginal seats, it can concentrate any anti-government swing in least marginal areas.
In both 1998 and 2010, first-term federal governments suffered swings that should have thrown them out of office, if the swings were uniform. John Howard’s Coalition government lost the national two-party-preferred vote in 1998 and Julia Gillard’s Labor government barely scraped by in 2010. But both governments benefited from sophomore surges to their marginal seat MPs that helped hold back the tide.
There are other theories for why we see these results. The winning party will often claim credit for “sandbagging” their key marginal seats and, conveniently, the narrative will usually assume that the government had a superior marginal seat campaign. But this explanation doesn’t explain why one party was so much better at targeting the key seats and why this effect isn’t systemically favouring one side over the other.
Labor needs to win 14 seats to deprive the Coalition of a majority and 19 seats to win their own majority.
Fourteen of the 20 most marginal Coalition seats are held by an MP who defeated a Labor MP in 2013, so we should expect a sophomore surge effect in many of these seats.
In the regional NSW seats of Page and Eden-Monaro, the defeated Labor MP is returning for another go, which should counteract any personal vote effect.
In two other seats, new Coalition MPs replaced retiring MPs in 2013 (a Liberal MP in Gilmore and a Labor MP in Capricornia). The LNP will be suffering from the loss of the personal vote of sitting MP Teresa Gambaro in Brisbane.
On the other side of the pendulum, Labor could have a fight on its hands to hold on to the marginal Melbourne seats of Bruce and Chisholm, where the longstanding MPs are retiring. These two seats are held on slim margins. The statewide trend suggests a slight shift to Labor, but the loss of the personal vote in these two seats could see them buck that trend.
Three Liberal seats in New South Wales were redrawn as notional Labor seats in the redistribution. In two of these seats, Barton and Dobell, first-term Liberal MPs should benefit from a new personal vote that may give them a chance to buck the trend, despite the seat having a Labor majority. Liberal Bob Baldwin is retiring as the member for Paterson, and the combination of lost personal vote and adverse boundary changes appears to have left the Liberal party struggling to hold on.
Not every race will follow this pattern. Some MPs are better than others at building a personal vote but with 14 of the 20 most marginal Coalition seats benefiting from this effect, it does make it harder for Labor to win.
None of this is to say that Labor can’t win – the race is very close and marginal seat polls suggest that a large number of seats are in play. But if the election is as close as the polls are suggesting, the Coalition will have an edge.
