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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Richmond is a victory for hope - now let's bring change across the country

The regressives are building their armies. 

Last night a regressive alliance was toppled. Despite being backed by both Ukip and the Conservative Party, Zac Goldsmith was rejected by the voters of Richmond Park.

Make no mistake, this result will rock the Conservative party – and in particularly dent their plans for a hard and painful Brexit. They may shrug off this vote in public, but their majority is thin and their management of the post-referendum process is becoming more chaotic by the day. This is a real moment, and those of us opposing their post-truth plans must seize it.

I’m really proud of the role that the Green party played in this election. Our local parties decided to show leadership by not standing this time and urging supporters to vote instead for the candidate that stood the best chance of winning for those of us that oppose Brexit. Greens’ votes could very well be "what made the difference" in this election (we received just over 3,500 votes in 2015 and Sarah Olney’s majority is 1,872) - though we’ll never know exactly where they went. Just as importantly though, I believe that the brave decision by the local Green party fundamentally changed the tone of the election.

When I went to Richmond last weekend, I met scores of people motivated to campaign for a "progressive alliance" because they recognised that something bigger than just one by election is at stake. We made a decision to demonstrate you can do politics differently, and I think we can fairly say that was vindicated. 

There are some already attacking me for helping get one more Liberal Democrat into Parliament. Let me be very clear: the Lib Dems' role in the Coalition was appalling – propping up a Conservative government hell bent on attacking our public services and overseeing a hike in child poverty. But Labour’s record of their last time in office isn't immune from criticism either – not just because of the illegal war in Iraq but also their introduction of tuition fees, privatisation of our health service and slavish worship of the City of London. They, like the Liberal Democrats, stood at the last election on an austerity manifesto. There is a reason that we remain different parties, but that doesn’t mean we shouldn't also seize opportunities like this to unite behind what we have in common. Olney is no perfect candidate but she has pledged to fight a hard Brexit, campaign against airport expansion and push for a fair voting system – surely progressives can agree that her win takes us forward rather than backwards?

Ultimately, last night was not just defeat of a regressive alliance but a victory for hope - a victory that's sorely needed on the back of of the division, loss and insecurity that seems to have marked much of the rest of this year. The truth is that getting to this point hasn’t been an easy process – and some people, including local Green party members have had criticisms which, as a democrat, I certainly take seriously. The old politics dies hard, and a new politics is not easy to forge in the short time we have. But standing still is not an option, nor is repeating the same mistakes of the past. The regressives are building their armies and we either make our alternative work or risk the left being out of power for a generation. 

With our NHS under sustained attack, our climate change laws threatened and the increasing risk of us becoming a tax haven floating on the edge of the Atlantic, the urgent need to think differently about how we win has never been greater. 

An anti-establishment wave is washing over Britain. History teaches us that can go one of two ways. For the many people who are utterly sick of politics as usual, perhaps the idea of politicians occasionally putting aside their differences for the good of the country is likely to appeal, and might help us rebuild trust among those who feel abandoned. So it's vital that we use this moment not just to talk among ourselves about how to work together but also as another spark to start doing things differently, in every community in Britain. That means listening to people, especially those who voted for Britain to leave the EU, hearing what they’re saying and working with them to affect change. Giving people real power, not just the illusion of it.

It means looking at ways to redistribute power and money in this country like never before, and knowing that a by-election in a leafy London suburb changes nothing for the vast majority of our country.

Today let us celebrate that the government's majority is smaller, and that people have voted for a candidate who used her victory speech to say that she would "stand up for an open, tolerant, united Britain".  But tomorrow let’s get started on something far bigger - because the new politics is not just about moments it's about movements, and it will only work if nobody is left behind.

 

Caroline Lucas is the MP for Brighton Pavilion.