As a general matter, that approach can work poorly when government debt is low. That is because a government that persistently holds debt to low levels obviously does not face the problem of improving its budget position so as to offset debt increases. Techniques that identify fiscal virtue by examining the response to rising debt will therefore be biased against those governments.
Instead, much like confusing temperance with a drunkard who periodically goes on the wagon, they risk most readily ascribing virtue to those governments that, having let deficits spiral, are forced into drastic corrective action.
That said, the paper does develop three specific tests to pinpoint periods where significant shifts in fiscal policy occur. One of those tests selects 2003 and 2005-07 as years of Australian "fiscal imprudence".
That is the result Martin's story emphasises. But what Martin doesn't note is that the paper's other tests did not confirm that finding, and that the test he privileges is statistically unproven and, on the authors' own admission, unconventional. Indeed, that test gives many bizarre results. For example, it not only finds Italian governments to be consistent models of fiscal rectitude, but also singles out 2002-05 as years of fiscal prudence in Britain, even though that was when the Labour government's budget deficit blew out of control.
Precisely because of the difficulties of placing much weight on any such measure, the paper provides a table that combines its tests - and which does not identify any fiscal imprudence in the Howard years.
You wouldn't know that, however, from Martin's reporting. Nor would you know that the test he privileges uses data on gross, not net, debt (that is, gross debt minus gross financial assets).
Usually that will not matter, as the two vary together. But the distinction does matter, possibly substantially, for the Howard government.
That is because as net debt fell to zero, the Howard government faced a situation where it would not be issuing government bonds; but the interest rate on those bonds plays an important role as a reference point for financial markets, for example, in setting prices for bonds issued by corporations.
The government therefore continued to issue bonds, thus retaining gross debt, but offset those issues with purchases of other financial assets, so that net debt kept falling.
With gross and net debt thus moving separately, a test that only examines gross debt would incorrectly conclude the government imprudently failed to push fiscal consolidation as much as it could and should have done.