The Scottish government is to publish its latest calculation of taxation and spending in Scotland, as a guide to the health of Scotland’s public services.
The Government Expenditure and Revenue Scotland (GERS) publication has been brought forward from March next year.
The figures included will cover the financial year 2015-16.
They are likely to show the Scottish balance sheet still clearly in the red, even including a share of oil.
Last year’s GERS figures were gloomy, depicting Scotland with a 15bn deficit.
That was twice the UK level as a share of economic output.
It seems unlikely that Wednesday’s figures will be rosy.
Opposition parties in Scotland are expected to argue the stats point away from a positive case for independence.
But Scottish ministers will insist that Scotland’s economic foundations remain strong – and will again spotlight the challenge from Brexit.
This approach to estimating how much Scots pay in tax, and how much they benefit from spending at all levels of government, goes back to the early 90s.
Conservative ministers in the Scottish Office thought it would help inform the debate on devolution, or at least it would help them make their case against a Scottish parliament.
The numbers would show, they thought, how much more Scotland gained from the Treasury than it sent south in tax revenues.
That was one of those times when the oil price was low.
Seven years earlier, it was very high and oil revenues were like a gusher.
As we have come to learn from the annual battle to interpret the GERS numbers, the profitability of offshore oil and gas makes a big difference to how much Scottish public finances are in the red, or occasionally, in surplus.
One way of looking at them is to measure how big Scotland’s deficit would be, if the country were to have been both independent and if its public finances were performing exactly as they did within the UK.
It would probably perform rather differently if Holyrood pulled the tax, spending and borrowing levers in different ways to the Treasury in London.
It could have pulled those levers in a smarter way, or left a bigger deficit.
Everything around this is contested. But what can be said is that this helps illustrate the health or weakness of Scottish public finances.
The previous figures covering 2014-15 added estimated tax paid in Scotland to an estimate for the revenue that would have flowed from oil and gas profits made from fields in Scottish waters.
The Treasury offshore tax that year was 2.24bn, of which Scotland was allocated 80%. So the total tax revenue for Scotland came to more than 53bn.
The amount spent in Scotland, through Holyrood and through state pensions, benefits and other shared Westminster commitments, was 68bn. The difference – meaning the deficit Scotland would have had under these circumstances – was nearly 15bn.
For most of us, that’s too big a number to comprehend.
So let’s convert it into a share of Scotland’s national output.
That deficit amounted to nearly 10% of all the output from the Scottish economy that year.
That’s more than three times more than what is widely seen as a safe level of deficit. (Eurozone rules state the ceiling for deficit should be 3% of output, or Gross Domestic Product.)
The UK also ran a deficit that year, as it does most years.
But since 2010, George Osborne the former Chancellor has been trying, and sometimes struggling, to reduce it.
The year before last, the UK deficit was six times bigger than the Scottish one.
But the comparable share of total UK output was lower than Scotland’s, at less than 5%.
In other words, Scotland’s notional deficit was nearly double the scale of the UK one.
Looked at another way, the amount spent by governments on the average Scottish person was 12,800.
According to GERS, that’s 1,400 more than the average for the UK as a whole.
Why? You could argue that it’s because Scotland has greater needs, to cope with a higher level of ill-health.
You could say it’s because rural services in Scotland require a higher level of spending on roads and ferries and small schools.
But does it? Well, that’s less clear. The distribution of spending was shaped at a time when Scotland’s needs were greater, relative to the rest of the UK, than they have been in recent years.
And one question that arises from this is whether Scotland gets value for that extra money – 1,400 of extra value per person.
Are the outcomes of that higher spending really that much better?
A lot of the numbers that will determine the latest GERS figures are already known, from official publications for 2015 to 2016.
And one of the numbers that will change things is a further sharp drop in oil and gas revenues.
With a much lower price, high costs and tax allowances, tax revenue is low to the point of actually going negative.
One of those who has cast an expert eye over the available figures says the deficit measure for Scotland will be smaller, at about 9bn, while the UK deficit has fallen at a faster rate.
The gap between average Scottish spend per person, with oil and gas revenues negligible, has left a 400 per head gap in spending for Scotland, meaning the Scottish spending premium looks more like 1,800 per person.
We will find out later if that is correct. And then, the constitutional battle can be joined once again, with this fresh input of data.
What is new this year is the uncertainty over Britain’s public finances resulting from the vote to leave the European Union.
That’s forecast to lower economic growth and tax revenue, while raising spending through a rise in unemployment.
A day before GERS day, the first minister got her retaliation in early, using some equally big numbers to demonstrate the forecast impact of that Brexit vote.
Nicola Sturgeon’s point is to help illustrate that Westminster looks less of a safe haven for public spending than it might have appeared to be in the past.