Just imagine for a moment at the start of this election campaign that we had to pick a winner and there were no opinion polls to guide or confuse us. We would have to make a selection based on our own common sense assessment of the factors likely to influence Australians.

Sensibly we would start with incumbency. Historically the best guide to a coming result is the past one. Governments win far more often than Oppositions — at 20 of the 25 elections held since the end of World War II at which the contest has basically been between Labor and a coalition of the Liberal and National (once Country) parties. For the election of 2010 expecting a Labor victory would be the starting point.

The five occasions when the Opposition were victorious perhaps provide us with clues to the necessary conditions for it to happen again. In 1949 we had a Labor Government still imposing war-time policies of rationing on a people anxious to be rid of such economic controls. Perhaps more importantly Labor was taking on a powerful business interest group with its commitment to bank nationalisation.

No concern for Labor this time on that economic front following the party’s conversion to free market policies but a danger signal from having upset the mining industry with new tax plans. A judgment needs to be made on whether the new Prime Minister has made a sufficient reversal of this policy. The answer is probably yes but it is something that should be reconsidered as the campaign progresses.

The change of government in 1972 was very much the “it’s time” election where after 23 years in office the Coalition went to the polls with a bumbling Prime Minister in Billy McMahon with Labor led by an inspirational Gough Whitlam. No apparent parallel with 2010 but note the fact that the victory was quite a narrow one.

Economic chaos best describes the conditions in 1975 when the Coalition was returned to office. Once again that loss is of no current relevance.

The defeat of Malcolm Fraser’s Government in 1983 gives us guidance on at least one question. Changing a somewhat dour leader on the eve of a campaign for one with charisma is no handicap. Public misgivings about the ruthless way Bill Hayden was dispatched to make way for Bob Hawke quickly disappeared in most states as the campaign got under way. The one reservation to note is that Bill Hayden, like Kevin Rudd, was a Queenslander and the swing to Labor in that state of 2.6% was a full percentage point less than the average swing Australia wide.

With hindsight it seems a little strange that Paul Keating survived at his first attempt to be elected heading a government as Prime Minister in his own right until we remember that his opponent chose to campaign not only on Labor’s record of presiding over an economic recession but on the introduction of a goods and services tax as well. It was Keating’s second time around in 1998, when economic conditions were definitely on the improve, that the retribution came.

I’m not sure what to make of that result and the defeat of John Howard’s team in 2007 also suggests that a sound economy is not a guarantee that a government will be returned. The 2007 Coalition defeat does point towards a big change in industrial relations law being as big a problem for the conservative side of politics as a big new tax like the GST. No wonder that Tony Abbott is making such a thing about there being no return to Work Choices in the first term of any government of his.

On balance, the incumbency benefit this year would seem to fit the normal pattern of favouring the Government. I cannot identify any issues powerful enough to upset the tendency of people to stick with the lot we have. Labor might not have gained the kudos it deserves for acting so decisively to stave off the global financial crisis but on most measures economic conditions are not too painful for people. Inflation is low and interest rates, as the Reserve Bank keeps reminding us, are around their historical level. Unemployment is higher than it was earlier in the century but not at a level that is affecting public confidence as it appears to be on the way down and not up.

Clearly Labor has identified general disquiet in some areas about the provision of essential services lagging behind population growth but it would be surprising if that alone stoked enough anger to throw a government out. Julia Gillard has begun her campaign addressing this issue and no doubt will continue to do so.

A longer term concern about the future of the planet is in the same category of general disquiet but with the differences between Government and Opposition now being only at the fringes that too is unlikely to influence things much when it finally gets down to putting a ballot paper into the box.

My common sense verdict is that we will see the incumbent win again.