Osborne's dynamic plan

How a technical change in Treasury forecasting could help scrap the 45p tax rate.

At the Treasury Select Committee yesterday, in between being quizzed by MPs angry at the extent of the pre-budget leaks, George Osborne revealed that he was planning to enable the OBR to make greater use of so-called "dynamic scoring" when they prepare their economic forecasts – but only when examining tax plans. It may not sound it, but if he made that change, it would be a huge coup for the right.

Dynamic scoring is the practice of including behavioural changes in economic forecasts. Without it, in a static model, changes to revenue after something like a tax hike are facile to calculate. If VAT at 17.5 per cent takes in (say) £175bn, then VAT at 20 per cent will take in £200bn. Similarly, if you are trying to calculate the effects on government revenues of spending £100m buying new trains for the east coast main line, then you can conclude that it will cost £100m – you buy the new trains, everyone carries on riding the line, and nothing changes.

What a static model says is that people are blind to the effect that government actions have when they are choosing what to do. Clearly, that is untrue. But it is also very easy to calculate, which is why it has stuck around for so long.

Dynamic models include all these changes of behaviour. So when looking at a dynamic model for rail investment, you can take into account the fact that nicer trains will make people more likely to travel, boosting ticket revenue; and when looking at a dynamic model for VAT rises, you bear in mind the fact that as prices rise, people buy fewer things, so that an 11 per cent rise in VAT won't lead to an 11 per cent rise in VAT revenue.

The problem for economists is that dynamic models are a lot harder to calculate. Not only are there far more variables to take into account, but you open yourself up to more avenues of attack from political opponents. The combined effect of all the assumptions you must make means that your conclusions can be deeply flawed if you get too many wrong, and, as the IFS says (pdf), can "[open] the door to large controversies if these guesses are made – or perceived to be made – in a politically biased way." While static models contain assumptions that are obviously false, dynamic models still contain assumptions, which can still be just as false. And unlike static models, we can't know which ones these are until it is too late.

So why does George Osborne want to introduce dynamic scoring into OBR models? Does he believe that the government's economists have uncovered a breakthrough understanding in behavioural responses to government intervention?

A clue can be found in HMRC's report into the 50p tax rate, which found that dropping the rate down to 45p would cost far less than expected, because of expected behavioural changes. Indeed, this sort of dynamic thinking is the cornerstone of the Laffer curve, the economic theory that, past a certain point, increasing tax rates reduces revenues.

What Osborne will be hoping is that allowing the OBR to make its models more dynamic still will strengthen the rationale for scrapping the 45p rate entirely, as well as for cutting corporation tax all the way down to 20p by the end of parliament.

Yet while the OBR will be "informed" by these new dynamic models when it comes to tax policy, they won't be taking account of the same information when examining the justification for government investment, where, far from strengthening Osborne's preferred policy, it would weaken it. If dynamic scoring is indeed implemented in this narrow fashion, Osborne will have scored a stealth victory for future Tory policy.

Money on the mind: A 19th century phrenology chart. Credit: Getty

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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Why I’m thinking of joining the Labour Party

There’s a lot to admire in the direction Jeremy Corbyn is taking the party – perhaps it’s time to get involved.

Why I'm leaving Labour”, as Owen Hatherley remarked a few days ago, appears to be the new “why I’m leaving London”. However, aside from a few high(ish) profile departures, the bigger story is the net increase in membership of 90,000 that Labour has enjoyed since Jeremy Corbyn became leader. Indeed, the last few weeks have got me seriously considering whether I should add to these impressive numbers and join the party myself.

For me, one of the most cheering pieces of news since Corbyn’s victory was the convening of an advisory committee to shadow chancellor John McDonnell, including policy and academic heavyweights such as Mariana Mazzucato, Ann Pettifor, Joseph Stiglitz and Thomas Piketty. It was a clear indication that some fresh and serious thought was going to be put into the creation of a plan for remaking and rejuvenating the British economy. The early signs are that Labour will be offering a dynamic, high-tech economy of the future, with good pay and job security at its heart, which will stand in sharp contrast to the miserable Randian dystopia George Osborne has been pushing the country into during his time at the Treasury.

Also refreshing has been Corbyn’s use of Prime Minister’s Questions to give a voice to those affected by austerity. Given that our media and political class is disproportionately populated by people from privileged backgrounds, it’s really important that an extra effort is made to ensure that we hear first-hand from those bearing the brunt of these policies. It’s right in principle, and it turns out to be good politics as well. Because apparently many Conservative MPs are too stupid to realise that responding to the concerns of working class people with loud, derisive braying merely provides the public with a neat and powerful illustration of whose side each party is on.

Corbyn has taken a lot of flak in the media, and from MPs on the Labour right, for his response to the Paris attacks. But as someone who researches, teaches and writes on British foreign policy, Middle East politics and security issues, my admiration for the Labour leader has only grown in recent days.  

In the atmosphere immediately after a terrorist atrocity, a discourse emerges where caring about the victims and being serious about dealing with the threat are taken to be synonymous with advocating military responses and clampdowns on civil liberties, irrespective of the fact that fourteen years of pursuing this approach under the “war on terror” has only served to make the problem far worse. At times like these it takes a great deal of courage to articulate a careful, cautious approach emphasising non-military forms of action that address root causes and whose effects may be less dramatic and immediate. Many people were simply not in the mood to hear this sort of thing from Corbyn, but his policies are objectively more likely to make us safer, and I admire him for not being intimidated into silence despite the gallons of vitriol that have been poured on him.

In general, on national security, there is something heavily gendered about the narrative that casts the alpha male Cameron keeping Britain safe versus the dithering milquetoast Corbyn who doesn't understand the harsh realities. We reached the nadir of this stone age machismo during the last election campaign when Very Serious Jeremy Paxman put it to Ed Miliband that he couldn’t have Vladimir Putin in a fight.  After the disasters of the last decade and a half, the time is right to articulate a more intelligent, sophisticated alternative to the expensive, counterproductive militarism of the Conservative Party and the Labour right wing.

The question of whether Corbyn can win an election is certainly one that preoccupies me. He will struggle to attract voters to his right just as Yvette Cooper, Andy Burnham or Liz Kendall would have struggled to win back votes Labour lost to the SNP and the Greens. Enthusing and rallying the perhaps 30 per cent of the electorate who are broadly on the left is one thing, but adding the other 6-7 per cent that you need to win an election is another challenge altogether. Corbyn and his team have been on a steep learning curve since their shock victory in September, and they urgently need to clarify their message and improve their media strategy. Almost all the corporate press are bound to remain hostile, but there are ways to provide them with as little ammunition as possible.

More importantly, Corbyn’s team need to find ways of connecting directly with the public and bring them actively into what he's trying to do. In the current anti-politics mood, an opposition party based on a genuine, engaged mass movement could be a formidable force. Initiatives like “Momentum” will need to make quick and substantial progress.

Fundamentally, Corbyn’s Labour has to do what everyone concerned with genuine social progress has had to do throughout history: articulate points of view that go against prevailing orthodoxy, and do so in as persuasive a way as possible. By definition, these are battles against the odds. But you can't win them if you don't fight them. And for me, and I think most people on Corbyn's part of the left, five years of austerity have taken us beyond the point where we can accept the least worst version of the status quo. That prospect has simply become too painful for too many people.

So will I join? I’m still unsure. Without doubt there will be times when the leadership needs constructive, even robust criticism, and as a writer and researcher I may feel more free to articulate that outside of the Labour tribe. But whatever choice I make, the point for me is that this isn’t really about Jeremy Corbyn so much as the wider movement he represents, demanding a real change of course on politics, economics and foreign policy. That collective effort is something I will certainly continue to play an active part in.

David Wearing researches UK-Saudi-Gulf relations at the School of Oriental and African Studies, where he teaches courses on Middle East politics and international political economy. He sits on the steering committee of Campaign Against Arms Trade.