Two Doctors: How the Budget works.

It's that time of year again, and the first vote on the Scottish Budget will take place on Wednesday. Manufacturers of nail-clippers, beta-blockers and booze will expect a spike in sales at Holyrood between now and the 3rd of February, the scheduled date for Stage 3.

Speculation is rife, and the multi-handed game of very important poker is underway. Eddie Barnes thinks us Greens won't get what we want this year, while Jeff predicts a SNP/Tory/Green majority for.

Either way, some of the number-crunching out there is flawed. The key thing to remember with the maths is this: Stage 1 and Stage 3, the two parts where Parliament as a whole normally votes on the Budget, are different in a small but crucial way.

At Stage 1, if the vote is tied the Presiding Officer will vote to allow the Budget through to Stage 2. His responsibility is to stick to the status quo, and his (very reasonable) interpretation last year was that continued discussion is the status quo.

By Stage 3, though, status quo has been defined by the PO to mean last year's Budget. A 64-64 tie (or some other tie with abstentions) and he'll vote the current Budget down, just as he did last year.

Therefore, John Swinney needs, assuming no abstentions, no party splits, and no missing MSPs, 64 at Stage 1 and 65 at Stage 3.

To correct Jeff's numbers, the combinations for a minimal Stage 1 success can be:

SNP + Labour = 93

SNP + Tories + Lib Dems = 79

SNP + Tories + Greens = 65

SNP + Lib Dems + Greens = 65

SNP + Tories + Margo = 64

SNP + Lib Dems + Margo = 64

By Stage 3, those last two have dropped off. With those assumptions above, Margo can't influence that vote: the SNP need either Labour or any other two parties to back them.

Having spent years jousting indirectly with Margo when I worked for the first two Presiding Officers, I didn't expect my opinion of her to warm, but it has. She's got an extraordinary tactical nous, a fearless ability to stand up for unpopular causes on principle, and she's funny. She's done very well through the SNP's previous Budgets, and I suspect, arithmetic notwithstanding, she'll do so again.

David Doherty, Scottish Greens: why I'm standing in Glasgow North East

Over the last few years, Glasgow has become one of the Greenest parts of Scotland, and Glasgow North East is no exception.

Glaswegians are represented at Holyrood by Patrick Harvie MSP, and the city has returned five Green Councillors, one of whom, my colleague Kieran Wild, represents Canal Ward here in Glasgow North East.

In the Euro-elections Greens came third in Glasgow North East, ahead of the Conservatives and the Lib Dems, although it'd be dishonest to put out a leaflet saying "only Greens can win here".

It's not hard to see why Glasgow's increasingly backing the Greens. Our major campaign at Holyrood over the last year has been to try and insulate all of Scotland's homes, cutting bills, boosting jobs, tackling fuel poverty and beating climate change all in one go. As a volunteer I'm on the board of a building renovation charity, and I'm only too aware of the problems in this area across the city. The parties who've governed Glasgow, locally and nationally, should be ashamed of themselves for letting people continue to suffer in damp, unhealthy and expensive homes.

What's more, Labour and the SNP may be bickering about GARL, but only the Greens have consistently opposed the M74 currently being bulldozed through the South East of the City. We could have had Crossrail built by now for a fraction of the cost of this motorway, but sadly only Greens continue to make that case.

Finally, Glasgow's economy has taken a serious blow from the credit crunch and the recession, and people are understandably reluctant to back any of the parties who celebrated the risk-takers, backed the deregulators and handed over vast amounts of our money to the bankers. Pretending it all never happened isn't a long-term response to this crisis, nor is it a sustainable one.

So, let me be the first candidate to admit this election isn't in the bag for us, but we are part of the world's fastest-growing political movement, and we have confounded the naysayers who said we couldn't get MSPs, MEPs or Councillors elected. Sometime soon I'm confident we'll make that Westminster breakthrough, and people in Glasgow North East can be the first to deliver that radical change.