In a post at his very useful Oz Politics Blog during the week Bryan Palmer said:
We know from past election studies that roughly half the electorate reports that it decided how to vote during the election campaign.
The source of this statistic is probably the Newspoll conducted after each election that asks voters which party they voted for and then follows up with ‘when did you yourself finally decide to vote for …. party?’ In 2004, 30% of voters gave various times in the last week, and another 19% in the last month (ie, during the campaign). That makes 49%. Similar numbers were recorded in the 2001 election (46%), the 1998 election (50%) and even the 1996 election in which the baseball bats had supposedly been out for Paul Keating since the ‘recession we had to have’ (43%).
The Australian Election Study comes up with generally lower, but still significant, proportions of late deciders. They ask ‘when did you decide how you would definitely vote in this election?’, and adding up the answers from ‘about the time the election was announced’ to ‘election day’ we get 38% in 2004, 41% in 2001, 51% in 1998, and 38% in 1996.
But does this exaggerate the impact of the campaign? There are a couple of reasons for thinking that we should put a lot of emphasis on the ‘finally decide’ in Newspoll and the ‘definitely vote’ in the AES.
Before the election, Newspoll also asks voters how certain they are to vote the way that they have just indicated. It finds that only a fairly small proportion of voters are still very undecided. In the final poll before every election since 1996 a remarkably consistent 9% have agreed with the proposition that ‘you could vote this way but there is just as much chance that you will vote for someone else’. A larger minority, of (depending on the election) 22%-31%, agree with the proposition that ‘you will probably vote this way but there is a slight chance that you may vote for someone else’.
In the last couple of elections Newspoll has also asked the certainty question in the months leading up to an election. The highest proportion of voters saying that they could go either way was 18% in June 2001, five months before the election. It was down to 13% early in the 2001 campaign and 10% early in the 2004 campaign. These numbers suggest that the overwhelming majority of people have made a certain or provisional decision before the campaign starts.
There is other political science research consistent with these Newspoll findings. In the Australian Election Study, more than 80% of voters nominate a party when asked: ‘Generally speaking, do you usually think of yourself as Liberal, Labor, National or what?’ The AES also asks people who they voted for at the most recent election and who they voted for the election before that. In the last two surveys, just over three-quarters of respondents who voted at the previous election say they voted for the same party both times. (Though new voters are likely to be less stable in their political preferences.)
The proportion of voters who rely on the campaign for their decision, then, isn’t 50% or anything close to it. It’s probably not even 20%, once we take out those whose vote is a random marking of the ballot paper intended to avoid being fined for not voting rather than to give a verdict on the campaign. Another 30% are probably going to vote according to a choice already provisionally made, often influenced by their general support of a party, but have not made a final or definite decision.
Of course the campaign is still very important – not just to persuade the very uncertain, but for the parties to ensure that supporters who are not rusted on do in fact vote for them on election day. But the electorate is not as volatile as people might think, if they just looked at surveys on when the final voting decision is made.