Is there any body in the UK that parallels the American Congressional Budget Office? One that could give a best estimate of the costs of various Brexit options? Obviously it’s very complex and the range and margin of error in their work would be large (as is a lot of the work the CBO does), but why not deploy a group to get these estimates?

  • Is this really a Brexit question? Or is the real question if there is a UK equivalent of the CBO?
    – Brythan
    Jul 30, 2019 at 2:36
  • Per Brythan's comment, I've removed the focus on Brexit. Since I've answered about the UK equivalent, you can now ask what that office has laid out about various Brexit options. To keep the scope nice and small, you might want to ask about different options separately, or ask something specific on how different options compare (e.g. how do Brexit options A, B and C deal with policy X / who pays for Y).
    – JJJ
    Jul 30, 2019 at 3:23

1 Answer 1


That would be the OBR, the Office for Budget Responsibility. From Wikipedia:

The Office for Budget Responsibility (OBR) is a non-departmental public body funded by the UK Treasury, that the UK government established to provide independent economic forecasts and independent analysis of the public finances. It was formally created in May 2010 following the general election (although it had previously been constituted in shadow form by the Conservative party opposition in December 2009) and was placed on a statutory footing by the Budget Responsibility and National Audit Act 2011. It is one of a growing number of official independent fiscal watchdogs around the world.

The five main roles from its own website:

  • Economic and fiscal forecasting to accompany the Autumn Budget and Spring Statement;

  • evaluate the Government’s performance against its fiscal targets;

  • assess the long-term sustainability of the public finances and analyse the public sector’s balance sheet;
  • evaluate fiscal risks from 2017; and
  • scrutinise tax and welfare policy costings at each Budget.

A more detailed explanation of those 5 points are also found on the OBR website:

  1. ECONOMIC AND FISCAL FORECASTING We produce detailed five-year forecasts for the economy and public finances twice a year. The forecasts accompany the Budget Statement (usually in late November) and the Spring Statement (usually in March). They incorporate the impact of any tax and spending measures announced in those statements by the Chancellor.

    The details of the forecasts are set out in the Economic and fiscal outlook (EFO). Our annual Forecast evaluation report (FER), published each autumn, examines how they compare to subsequent outturns and draws lessons for future forecasts. For a description of the forecasting timeline, read about our forecast process on the forecast methodology page.

  2. EVALUATING PERFORMANCE AGAINST TARGETS We use our public finance forecasts to judge the Government’s performance against its fiscal targets and target for welfare spending. In January 2017 the Government set itself two new medium-term fiscal targets: first, for the structural deficit (cyclically adjusted public sector net borrowing) to be below 2 per cent of GDP by 2020-21; and second, for public sector net debt to fall as a share of GDP in 2020-21.

    In each EFO, we assess whether it has a greater than 50 per cent chance of hitting these targets under current policy. Since March 2014, the government has also set a self-imposed cash limit on a subset of its social security and tax credit spending (the ‘welfare cap’). In Autumn Statement 2016 the Government redefined the cap so that it applies only in 2021-22, preceded by a ‘pathway’ to that fixed date. The Charter requires the Government to set a new welfare cap in the first Budget of a new Parliament so in Autumn Statement 2017, the cap was adjusted and applied to 2022-23. We monitor progress against the pathway and assess whether or not the government is on course to meet the cap in the target year in each EFO.

    Our annual Welfare trends report (WTR) examines the drivers of welfare spending, including both those elements inside and outside the cap.

  3. SUSTAINABILITY AND BALANCE SHEET ANALYSIS We assess the long-term sustainability of the public finances: Our Fiscal sustainability report (FSR) sets out long-term projections for different categories of spending, revenue and financial transactions, and assesses whether they imply a sustainable path for public sector debt.

    The FSR also analyses the public sector’s balance sheet, using both conventional National Accounts measures and the Whole of Government Accounts (WGA) prepared using commercial accounting principles. From 2016, the FSR will be published once every two years, reflecting the frequency with which the Office for National Statistics updates its population projections.

  4. EVALUATION OF FISCAL RISKS Every two years we produce a comprehensive review of risks from the economy and financial system in the Fiscal risks report (FRR). The first FRR was published in July 2017 where we analysed tax revenues, public spending and the balance sheet, and included a fiscal stress test. In addition to producing central forecasts and projections for the public finances, the EFO and FSR include discussion of the risks to those forecasts and projections (both upside and downside). The WGA also provides further information on specific fiscal risks, notably contingent liabilities (such as government guarantees), which we discuss in the FSR.

  5. SCRUTINISING TAX AND WELFARE POLICY COSTING We scrutinise the Government’s costing of individual tax and welfare spending measures at each Budget. The Government provides us with draft costings in the run-up to each statement and we subject these to detailed scrutiny and challenge.

    We then state in Annex A of each EFO and in the Treasury’s policy costings document whether we endorse the costings that the Government finally publishes as reasonable central estimates and whether we have used them in our forecasts. We also give each costing an uncertainty rating, based on the data underpinning it, the complexity of the modelling involved and the possible behavioural impact of the policy.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .