The gist of my forecast was that Abbott would win the top office in 2013 but that he would prove to be the least successful conservative elected prime minister since Canberra became the national capital in 1927.

Before I continue to argue the correctness of my predictions, I should define the term ''elected prime minister''. To me, such a person is the one who takes their party from the opposition benches onto those of the government, courtesy of a victory at a general election.

A list of postwar elected prime ministers (defined in that way) is provided in the accompanying table, titled ''House of Representatives strengths of newly elected governments''.

The seven men are ranked according to the strength of his first election victory. However, that ranking is subject to the qualification of certain extra details, which are provided below.

It can be seen that the four most successful men were all from the Liberal Party while Labor provided only one prime minister (Bob Hawke) whose first victory even enjoyed the description of that undefined term - ''landslide''. I give below certain reasons to suppose that the first Hawke victory of March 1983 was actually stronger than that of Abbott in September.

In predicting that Abbott ''would prove to be the least successful conservative elected prime minister'', I might have included in my table the case of Joseph Lyons, who led the conservative forces to victory over Labor's James Scullin in December 1931. However, there was no need to include Lyons. If I had decided to include him, he would have topped the table. On every measure, Lyons had a bigger victory than Malcolm Fraser in December 1975.

So let me consider the conservatives, so far.

Lyons won three general elections (in December 1931, September 1934 and October 1937) and held the office of prime minister for seven years and three months before becoming the first prime minister to die in office in April 1939.

Robert Menzies was prime minister in his second term from 1949 to 1966, retiring on his own terms in January of that year. He won seven general elections - in December 1949, April 1951, May 1954, December 1955, November 1958, December 1961 and November 1963.

Fraser was prime minister for seven years and four months and won three elections - in December 1975, December 1977 and in October 1980.

Howard was prime minister for 11½ years and won four times - in March 1996, October 1998, November 2001 and October 2004.

In effect, I am predicting that Abbott will win only two elections, in 2013 and 2016, and be defeated in, say, December 2019, having served in the top job for six years and three months. However, I would not be surprised if his Abbott's term is less than six years.

It can be seen from the table that the relative strength of a first victory can prove an unreliable long-term guide. Were it to have been a good guide, then Fraser would have been more successful than Howard and Menzies.

Curiously enough, however, on the Labor side, it has been a good guide. Hawke had the most impressive first victory and served the longest. Gough Whitlam had the weakest first victory and, when he was defeated, he was the most heavily defeated - with 55.7 per cent of the two-party preferred vote cast against him compared with only 53.5 per cent cast against Rudd. See table.

I found it interesting that Howard recently wrote some extra words for a new edition of his autobiography, Lazarus Rising. Being Abbott's great backer, he was naturally inclined to say how well Abbott had been travelling. In particular, he was inclined to say how great the Abbott election victory had been.

Yet all Howard could say was that Abbott had a bigger first victory than Whitlam or Rudd. True, but I am not sure Abbott would enjoy the inference that his term as prime minister would last for less than three years.

Howard conspicuously did not suggest that Abbott had a bigger first victory than Hawke. I know from conversations with Howard that he describes the first Hawke victory as a ''landslide''. I have no idea what term he would use to describe Abbott's victory.

For me, the most striking thing about the Abbott election win was the Coalition's very poor performance in the Senate election. So let me give the Senate percentages for the winning prime minister's party listed in my table, excluding Whitlam since there was no Senate election in 1972.

The percentages are: Fraser 51.7, Menzies 50.4, Hawke 45.5, Howard 44.0, Rudd 40.3 and Abbott 37.7.

I do not have much difficulty persuading people that Abbott's win was not a landslide. My problem is that I insist on defining the term before I give a verdict. In my definition, three conditions must be met before an Australian federal election can be called a landslide.

First, the two-party preferred vote must be outside the range 55-45. Second, there must be a big swing. Third, a large number of seats must change hands.

Australia has had 44 elections, which is why the present Federal Parliament is called the 44th Parliament.

On my reckoning, only six of those 44 elections could be called landslides. In 1917, Billy Hughes scored the first landslide re-election of any government. The second case was that of John Curtin in 1943 and the third was the Harold Holt victory in 1966.

Landslide defeats for federal governments were those of Stanley Bruce in 1929, Scullin in 1931 and Whitlam in 1975. In all other cases, the result could be described as a ''respectable loss'' for the loser.

Malcolm Mackerras is a visiting fellow at the Public Policy Institute, Australian Catholic University, Canberra campus.

malcolm.mackerras@acu.edu.au