After much indecision, I have finally appended my South Australian election guide entries with predictions for each seat. To cut a long story short, I am tipping Labor to win 24 seats (loss of four), the Liberals to win 20 (gain of six), independents three (loss of one) and the Nationals zero (loss of one). I thus find myself tipping a one-seat Labor majority for the third state election in a row. In Western Australia I was only a seat or two out, but my error was crucially in the wrong direction, such that I missed the change of government. The Queensland election prediction was not one of my better performances: I made from memory seven wrong calls, each being a seat I wrongly thought the Liberal National Party would gain from Labor. Third time lucky, perhaps.

What follows are detailed rationales for the choices I’ve made. Two pieces of terminology which appear throughout require explanation: one familiar to election buffs the world over, the other of which I just made up. “Sophomore surge” refers to the advantage known to accrue to candidates who were first elected at the previous election, and are thus enjoying the advantages of incumbency for the first time. The effect is particularly pronounced where the member unseated a candidate of the opposing party at the previous election, as the incumbency advantage moves from one party to the other. So it was in most of the seats on which the election will hinge, which is a major advantage to Labor. In calibrating this effect I examined results from the 2002 and 2006 elections in Victoria, the former of which delivered Labor a mother lode of seats at the expense of their opponents. Of the 19 such seats, 16 delivered Labor better-than-average results in swing terms in 2006, the average swing to the Coalition being 1.6 per cent less than the statewide result.

“Donkey flip” refers to circumstances where the donkey vote favoured one party in 2006, but favours the other in 2010. The conventional wisdom says about 1 per cent of the electorate wantonly numbers the candidates in ballot paper order, so under preferential voting the vote ends up with whichever of the Labor or Liberal candidates is higher on the ballot paper. If it’s the same party at both elections, the value of the previous election as a guide to the current one is undiminished. But when it changes, a 1 per cent bonus must be factored in to whichever party picks up the benefit.

Light (Labor 2.4%): There are a number of reasons Labor has remained vaguely hopeful about Light in more optimistic moments, despite it being their most marginal seat. Labor member Tony Piccolo gets both the sophomore surge and donkey flip, so his natural margin might be said to be more like 5 per cent. Labor also believes the rapid growth of the area puts some wind in its sails because it has changed the electorate’s once-rural character, although the booth swings over the past decade have in fact matched the statewide results quite closely. In any case, the narrowness of the margin is such that a Labor win would be an upset. Those watching the seat’s progress on election night should note that it might behave erratically: it combines the heavily Labor outer suburbs of Munno Para and Smithfield Plains, the growing rural towns of Roseworthy and Angle Vale and the satellite city of Gawler which dominates it. Each of these might swing in different ways: even within Gawler itself there might be a division between the growing outer suburbs of Hewett and Evanston and the town centre, where voters might be taking unkindly to their region’s rapid transformation. In the final analysis though, this goes down as a Liberal gain.

Mawson (Labor 2.7%): Labor member Leon Bignell has sophomore surge going for him, but he has lucked out on the donkey vote both times. Mawson is also a growth area, but not necessarily in ways reassuring to Labor. Hackham in particular has been trending away from them as new housing developments emerge, while remaining strong in absolute terms. The trump card for Bignell, Labor would hope, is the Southern Expressway, on which Labor snookered the Liberals shortly before the campaign began. At that time the Liberals were compelled to put their own planned announcement on ice, saying details of its promise would be made available later in the campaign. That will presumably happen over the next few days, allowing them to at least neutralise the issue. Mawson might ultimately be a tougher nut to crack for the Liberals than other seats with bigger margins, but the margin being what it is I have it down as a Liberal gain.

Norwood (Labor 3.7%): Norwood went down to the wire in 1997 and 2002 before giving Labor its smallest swing of any Adelaide seat in 2006. The conventional explanation for the latter result was the popularity of the Liberal candidate, Adelaide Crows star Nigel Smart. Given that Smart is not the candidate this time, it might be thought the seat is safer for Labor than the margin makes it appear. However, long-term sitting member Vini Ciccarello is one of the few marginal seat defenders who won’t enjoy a sophomore surge, and the Liberals also get the donkey flip. Labor should also cop the brunt of the evident public preference for the Liberals’ Royal Adelaide Hospital policy, both due to the hospital’s proximity to the electorate and the large proportion of older voters (16.9 per cent of the population compared with 13.3 per cent nationally). Labor was also deeply concerned at how the land tax issue was playing in this and other eastern suburbs electorates, hence the government’s announcement at the end of January of $52 million in cuts that would in future spare 75,000 people out of 121,000 from having to pay it. The Save RAH and Fair Land Tax parties both have candidates in the field who are directing preferences to the Liberals. While the seat is not a lay-down misere, the weight of the evidence seems to favour a Liberal gain.

Newland (Labor 5.2%): The margin in Newland is below the statewide swing indicated by Newspoll and Galaxy, but there are a number of reasons to believe Labor has it sufficiently sand-bagged. Most obviously there is the 53-47 Advertiser poll from earlier in the campaign, notwithstanding that the paper’s methodology is believed to be less sophisticated than that of the established polling agencies. Labor member Tom Kenyon gets both sophomore surge and donkey flip, although the former is diminished by the fact that he was not opposed by a sitting member in 2006, which contributed to his massive 12.3 per cent swing. The electorate is distant from Royal Adelaide Hospital, although the much nearer Modbury Hospital carries dangers of its own for the government. Land tax was biting as an issue here, but the government’s aforementioned giveaway might have taken some of the sting out of it. Most significantly, the Liberals have almost certainly made a mistake in nominating the baggage-laden Trish Draper as their candidate. All that being so, Labor retain.

Hartley (Labor 5.6%): A difficult one. Grace Portolesi will benefit from sophomore surge, but it might be mitigated by the fact that she faces Joe Scalzi, the defeated Liberal member from the last election, who by all accounts has since kept up his profile in community groups and the locally numerous Italian community. Against that, there may be a stigma attached to a “recycled candidate”, and it appears Portolesi has worked her turf very effectively over the fortnightly garbage collection and Chelsea Cinema issues. Portolesi had the donkey vote both times, so that won’t be a factor. The Royal Adelaide Hospital is close enough to be a problem for Labor, and the electorate was an epicentre of discontent over land tax: it goes without saying that Save RAH and Fair Land Tax both have candidates here. Factoring all that in, the margin is right where you wouldn’t want it to be if you were trying to make a prediction. After swinging back and forth over the past few days, Vickie Chapman’s foolishness has brought me down on the side of Labor retain.

Morialta (Labor 6.8%): Adelaide has a reputation for swinging in a fairly uniform fashion, so it’s a remarkable fact that a seat this far down the pendulum is reckoned by some to be the likeliest Liberal gain. Some background to the 2006 election can help explain this. Observers on both side of politics speak in tones of wonder at the scale of defeated Liberal member Joan Hall’s surrender during the campaign. Always averse to door-knocking, she is said to have retreated entirely to the central campaign headquarters and was almost never to be seen in her own electorate. On the other side of the ledger, Morialta had not been part of Labor’s strategy in either 1997 (the electorate was then called Coles) or 2002, but was attacked by the party with a vengeance in 2006. Cultivating territory it had previously ignored, Labor found low-hanging fruit to be particularly abundant in the Housing Trust-dominated territory around Paradise, where it recorded awesome swings of over 15 per cent. This time it’s the Liberals whose campaign efforts have switched from moribund to frenzied. An important factor here is the resources and campaigning expertise brought to bear on the electorate by Christopher Pyne, member for the corresponding federal seat of Sturt, whose office is described by Labor sources as an “aircraft carrier” for the Liberals’ campaigning efforts. Joan Hall didn’t get much help from Pyne as she had made an enemy of him and other moderates when she switched her allegiance from Dean Brown to John Olsen in 1996, enabling the latter to depose the former as Premier. By stark contrast, current Liberal candidate John Gardner worked until very recently as a staffer to Pyne, who is understandably doing his best to smooth his protégé’s passage into parliament. There are still a few points in Labor’s favour: Lindsay Simmons is said to have worked the electorate conscientiously, and there is surprisingly no Fair Land Tax candidate in the field. However, the Liberals get the donkey flip. Early in the campaign The Advertiser produced a poll which had the Liberals 52-48 in front – the consensus is that this was about on the money. Liberal gain.

Bright (Labor 6.9%): The Liberals’ apparent failure to make inroads in this seat, demonstrated by last week’s 55-45 Advertiser poll result, seems to be largely down to the popularity of local member Chloe Fox. I suspect the Liberal strategy has been to concentrate efforts in a minimum number of specific seats to be in a position to form government, and Bright hasn’t been one of them. Chloe Fox of course should get a sophomore surge, although like Tom Kenyon in Newland she did not face a sitting member in 2006. She has had the donkey vote advantage on both occasions. By overwhelming weight of conventional wisdom, Labor retain.

Mitchell (Independent 0.6% versus Labor): I might as well toss a coin here. The consensus view is that Kris Hanna won’t be able to keep his head in front of the Liberal candidate, but they said that last time as well (myself included). The argument goes that the Liberal resurgence gives him too great a hurdle to clear, and he won’t be able to piggy-back as effectively off Nick Xenophon as he did last time (the Liberal candidate rather than Hanna will also get the donkey vote this time, but that’s a relatively minor consideration). Against that, when Labor sheds votes many of their erstwhile supporters prefer parking their vote with a neutral candidate to getting in bed with the enemy. On the basis that I wrongly wrote off Hanna last time, Independent retain.

Frome (Independent 1.7% versus Liberal): Whereas Mitchell is almost certain to be determined by who finishes second, it seems very likely in the current environment that Frome will finish as a straightforward two-horse race between independent member Geoff Brock and Liberal challenger Terry Boylan. Here too there is very little hard data to go on, but my intuition is that a Liberal resurgence will be too much for Brock, and that he will struggle to appeal outside his home base of Port Pirie and in the very different electoral terrain of the surrounding rural areas and Clare Valley. That being so, Liberal gain. UPDATE: In the warm light of the late morning (Perth time), I’ve thought better about this one. That “Liberal resurgence” should be cancelled out by the general tendency of oppositions to do better in by-elections, and Geoff Brock will have a lot of low-hanging fruit in the Clare Valley even if he doesn’t poll hugely well there in absolute terms: his vote in many of these booths at the by-election was below 10 per cent. So make that Independent retain.

Chaffey (Nationals 17.2% versus Liberal): The decline of Labor’s fortunes has changed Karlene Maywald’s association with the government from asset to liability. With Labor’s re-election in 2006 a foregone conclusion, it made sense for the Riverland to vote for a seat at the cabinet table. This time it’s a case of conservative rural voters facing a clear opportunity to contribute to the defeat of a Labor government. It’s been suggested this week’s announcement on River Murray flows will be a boon for Maywald, but my guess – and that’s all it is – is that irrigators would sooner credit the forces of nature than Mike Rann. Against that, the advantages of incumbency in a rural seat should never be written off: but on the other hand, independent Russell Savage lost his Victorian state seat of Mildura just over the border in 2006, which I didn’t see coming. The Advertiser poll at the start of the campaign showing Maywald ahead 50.5-49.5 doesn’t make my life any easier, but I’m told the Liberals are confident. That swings it for me: Liberal gain.

Elsewhere, it’s by no means unthinkable that independent Don Pegler will upset the Liberal applecart in Mount Gambier, a naturally conservative seat being vacated by retiring independent Rory McEwen. However, the Liberals probably did what needed to be done in endorsing local mayor Steve Perryman, despite the knowledge that he might emerge as a loose cannon. The retirement of Liberal veteran Graham Gunn in Stuart made it a hypothetical Labor gain, but that prospect has surely receded. The Liberals are heartened by the fact that Gunn is managing the campaign of their candidate Dan van Holst Pellekaan, and has been working hard to introduce him around the electorate. The Nationals might nab Flinders from the Liberals now that sitting member Liz Penfold is retiring, but I’m thinking it must be significant that I haven’t heard it discussed lately. Finally, the perception that the swings don’t seem to be landing in the marginals where the Liberals need them most raises the prospect that swings in non-marginal seats might be on a sufficient scale to deliver Labor a nasty surprise. Adelaide‘s margin of 10.5 per cent is less than the federal Coalition suffered in some Queensland seats in 2007, but the government has spent a lot of political capital keeping it happy and has a locally popular incumbent. Beyond that I could only speculate, but it would certainly take a brave punter to tip a swing of over 12 per cent in any seat without hard evidence.

Finally, a couple of snippets of campaign news.

• Déjà vu all over again in Mount Gambier, with occasional Poll Bludger comments contributor Michael Gorey resigning as editor of the Border Watch newspaper and journalist Sandra Morello being banned from covering the election campaign. Renato Castello of the Sunday Mail reports the latter event was occasioned when “the Liberal Party complained her husband and former Border Watch editor Frank Morello was writing media releases for (independent candidate Don) Pegler”, with three such releases said to have formed the basis for Morello’s stories (a common enough practice at hard-pressed suburban and regional newspapers, as I can state from personal experience). However, Gorey gave notice six weeks earlier, so the two events are presumably not related. Pegler denied suggestions his campaign was being bankrolled by the paper’s publisher, the Scott Group, which was owned by recently deceased trucking magnate Allan Scott. Frank Morello was himself stood down by Allan Scott during the 2006 campaign after the paper ran a number of articles seen to be critical of Liberal candidate Peter Gandolfi, whose well-financed campaign was believed to have been financed by Scott. This prompted the sudden resignation of Lechelle Earl, the writer of the articles and the paper’s chief-of-staff. When Gandolfi was defeated for preselection ahead of the current election by Steve Perryman, Scott wrote to the then Liberal leader Martin Hamilton-Smith threatening to back “any independent who might contest the seat”, according to Greg Kelton of The Advertiser.

• A timely “in-principle agreement” between the South Australian, New South Wales and Queensland governments will deliver South Australia 400 gigalitres in Murray River flows, courtesy of recent flooding in Queensland. This will be a boon to irrigators in the Riverland, and thus to Karlene Maywald in Chaffey. However, Shadow Water Minister Mitch Williams says Rann is claiming credit for being granted water that New South Wales “physically cannot keep”. The announcement came shortly after irrigators had their allocations increased to their highest level since October 2006 on the back of earlier flooding in New South Wales. Meanwhile, Tony Abbott has promised to hold a referendum on referring powers over the Murray-Darling Basin to the federal government if the states don’t agree to refer the powers voluntarily.

• Brad Couch of the Sunday Mail reports Labor strategists are considering a “whirlwind rural tour” for Mike Rann in the final week, the chief virtue of which is that such a tour paid handsome dividends for Anna Bligh at the end of last year’s Queensland campaign. One problem with this is that in stark contrast to Queensland, Labor in South Australia has no marginal seats it needs to defend in rural areas – unless Giles has emerged as a problem, or the party still holds out hope of gaining Stuart. Nonetheless, it is reckoned such a move might “portray Mr Rann as energetic and statesman-like”, thus countering the widespread perception he has looked tired during the campaign.

• That hardy perennial parish pump issue, the Britannia roundabout, has been targeted by the Liberals with a promised $12 million upgrade that will include the installation of traffic lights. An $8.8 million proposal to regulate the knotty five-way traffic snarl was scrapped by the Rann government in 2005. The roundabout is located at the junction of the electorates of Adelaide, Norwood and Bragg.

• Lauren Novak of The Advertiser reports the Greens have drafted laws to replace above-the-line voting with optional preferential voting for the upper house, apparently without a minimum number of boxes that must be numbered as usually occurs in similar cases elsewhere.