Of all the numbers subject to change in the next mid-year federal budget review, it seems pretty safe to say the predicted $1.5 billion surplus for this financial year will remain largely intact.
As rumours swirled in the corridors of parliament that the Mid-Year Economic and Fiscal Outlook will be released soon, earlier than in recent years, this week's Senate budget estimate hearings in Canberra provided some minor clues as to what to expect.
Treasurer Wayne Swan fuelled speculation about an October MYEFO release, telling the Australian Financial Review that most of the information needed to put the document together from a global perspective is already in hand.
Opposition Leader Tony Abbott said an early release would be unprecedented outside an election year and amount to the government "cooking the books".
But Treasury's executive director for the domestic side of its macroeconomics economics group, David Gruen, said waiting until the end of November for information would reveal who won the US presidential election, for example, but plenty of other things would remain unclear.
"We are in a world where uncertainty about the US and Europe will continue for years," Dr Gruen told the Senate's economics committee.
Looking at the International Monetary Fund's (IMF) latest round of world growth forecasts released last week, which featured sweeping cuts, Treasury's global predictions will be downgraded.
Seemingly on cue, Australia's number one trading partner, China, posted on Thursday its weakest annual growth in three years at 7.4 per cent for the September quarter.
However, despite this weak global profile, "quite significant" falls in iron ore and coal prices since the May budget, and a scaling back of resources investment, Treasury's assessment of Australia's real economy was "broadly similar" to May.
While Treasury had predicted "truly extraordinary" rates of mining investment, it would remain relatively high.
For example, according to the Australian Bureau of Statistics, investment growth will still be a rapid 45 per cent in 2012/13 after 75 per cent growth in 2011/12.
The Reserve Bank of Australia (RBA) took a similar view in the minutes of its October board meeting released this week, saying anticipated mining investment will still make a "significant contribution" to growth in the coming quarters.
"Nonetheless, the information that had become available suggested there was an increased likelihood of growth over the coming year being somewhat weaker than earlier forecast," the minutes said, adding that "public" or government demand would subtract from gross domestic product.
Acting Treasury secretary Nigel Ray, standing in for Martin Parkinson at the Senate hearings, said the national accounts were the most crucial data for conducting a full round of forecasting for MYEFO.
He said this work could take several weeks after the June quarter accounts are released in the first week of September but noted the earliest a MYEFO had been released in the past was October 15.
"The other most important piece of information for putting together either a budget or MYEFO, and usually the last thing we get, is government decisions," Mr Ray said.
And those, as you would expect, are being kept close to the collective chest, although there is a lot of angst about what could be cut to ensure a surplus is returned.
This includes speculation of billions of dollars being cut from superannuation tax concessions and a 25 per cent tobacco tax hike.
Westpac economists Bill Evans and Andrew Hanlan expect to see a revenue shortfall of $3 billion for 2012/13, largely due to a "downside surprise" in the terms of trade, which they see contracting by 9.75 per cent rather than the 5.75 per cent May estimate.
"However, a complication is that the 2012/13 year is well under way, hence any savings measures need to be timely in their impact," they said in a client note.
"There may be scope to redistribute expenditures and revenues between years, thereby reducing the savings task for 2012/13."
The Senate hearings were told a second $300 million "special dividend" in three years looks set to be handed over from the government-owned healthcare provider, Medibank Private, in 2012/13.
But according to Treasury, the revenue take from the minerals resource rent tax that started on July 1 won't be known until late October.
It was estimated to earn $3 billion in 2012/13, but weaker commodity prices will drag on revenue.
Returns from the carbon tax that also started in July won't be known with any certainty until 2013.
Future spending on the National Insurance Disability Scheme, other than the $1 billion already set aside for its launch sites, would not be included in budget figuring beyond the four-year estimates until it became a definite item.
Beyond the $1.5 billion surplus in 2012/13, a significant turnaround from a $43.7 billion deficit in 2011/12, the budget is projected to remain in the black for the next three financial years.
Finance Secretary David Tune, whose department is the other key adviser in compiling the budget and MYEFO, said the goal of returning to surplus went beyond finding further savings in MYEFO.
"It is an ongoing task," he told the hearings.
