Nick Xenophon’s new SA Best party has done quite well in statewide polls, suggesting that he could wreak havoc on the South Australian party system by winning a large number of seats and forcing the major parties to work with him in a hung parliament.

Yet our first taste of seat-level polling suggests that the party may not be doing quite as well as the more optimistic statewide polls would imply.

Recent statewide polls have put SA Best on a vote somewhere between 18% and 32%. If SA Best can come close to 30%, you’d expect them to break into the top two candidates in a large number of seats and win a sizeable proportion of seats – possibly more than one of the major parties. A vote of 18% would be impactful, but may only be enough to win a handful of seats.

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The Nick Xenophon Team (NXT) polled 21.7% in the Senate in South Australia at the last federal election. After distributing preferences from minor candidates between Labor, Liberal and Xenophon, this figure climbed to 27.2%. These voting figures have been split between the 47 state electorates to give us an estimate of underlying support for Xenophon’s party. The NXT vote after distributing minor preferences ranged from 21.7% in Croydon to 38.5% in Heysen. This vote was enough to put NXT in the top two parties in 23 out of 47 seats.

If SA Best could poll something similar to this Senate vote, they’d be on track to win quite a few seats and make it hard for either party to win a majority. But seat polls in four electorates suggest SA Best is not on track for such a good result.

YouGov Galaxy has conducted four electorate polls: the first two in Lee and Morialta.

Lee ranked 40th out of 47 electorates for NXT in 2016, with a vote of 23.4%. This poll puts SA Best on 18%, with Labor leading Liberal 39% to 34%. This is down a bit on the NXT vote, but on its own may not mean much, since it’s not a seat likely to be a priority. It does, however, suggest that we are right to expect SA Best preferences to be vital in deciding results. An 18% primary vote would be crucial to determining whether Labor can hold on to this seat.

The poll in Morialta is less encouraging. NXT polled 31.8% there in 2016, but SA Best is only on 25% in this poll. This is enough to overtake Labor (21%) but well short of the Liberal primary vote of 40%. SA Best could conceivably win this seat, but it would require a very strong Labor preference flow. This was NXT’s sixth-best seat in the state. If the party was really on track for a double-digit seat haul, they should be doing better here.

Two more polls were conducted last week. The result in the massive rural seat of Giles is more positive. NXT polled 30.5% in 2016, and SA Best is now sitting on 31%, behind Labor on 37%. This seat seems eminently winnable with a Liberal vote of 23% available to be distributed as preferences.

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The most concerning result for SA Best came in Heysen. This seat lies deep in Rebekha Sharkie’s federal electorate of Mayo, and was the best seat for NXT at the 2016 election, with a vote after preferences of 38.5% (although this would include preferences from the Greens). Last week’s YouGov Galaxy poll put SA Best on only 22%, with the Greens on 16% and Labor on 15%. The Liberal party is well out in front, on 39%. The pollster estimates that SA Best would fall just short of winning after preferences.

If SA Best is struggling to win in Heysen, it suggests that they are likely to be headed for a result at the lower end of the polling range, rather than going toe-to-toe with the major parties.

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Of course we should be cautious with individual electorate polls, which have not always been as accurate as statewide polls, but there is a clear trend in the handful of seats polled so far. Hopefully we will see more polls over the last two weeks of the campaign, which will give us more of a picture of how the election is shaping up, but right now it would make more sense to predict an SA Best vote under 20%, producing a handful of seat victories, rather than a high vote leading to over ten victories.

These seat polls also confirm something else we’ve suspected: preferences will be crucial in this election, and a lot of seats could go down to the wire. When there is a third candidate polling well into double figures, their preferences will be decisive in the result. With SA Best opening up races in previously safe seats, the field of battle widens to include more marginal electorates. Whether or not Nick Xenophon’s new party is able to win a large number of seats off the major party, this will almost certainly be a complex election with some big surprises.