You asked
Please provide the following:
How many times has the GDP calculation been revised?
When was it revised?
What changes were made to the calculation, and why was it revised?
We said
First published in 1952, the Blue Book presents a full set of economic accounts (national accounts) for the UK. These accounts record and describe economic activity in the UK and, as such, are used to support the formulation and monitoring of economic and social policies. The UK adheres to the European System of Accounts 2010 (ESA 2010) which is based upon the UN System of National Accounts 2008 (SNA 2008), in the production of economic statistics published in the Blue Book. Prior to these editions, the UK also followed the production methods set out in ESA 1995 and SNA 1993.
While the calculation of GDP has remained the same over time, our GDP Quality and Methodology Information document provides details of the process used to compile GDP and the recent addition of Monthly GDP estimates. Revisions to National Accounts data are a normal part of the Blue Book process, which reconciles the different measures of GDP and incorporates information from annual data sources. GDP revisions can be categorized according to reasons; however, it is subsequently very difficult to quantify specifically the amount of revision due to any one reason in any given period as several reasons will almost certainly apply to each vintage of GDP. The reasons for revisions are as follows.
- Revisions to a source
- Replacing nowcasts with data
- Annual benchmarks
- The supply and use table compilation process
- Revised seasonal adjustment factors
- Updating the output weights
- New methods
- New international standards
Further information can be found in a past revisions article found here.
The following text sets out the main methodological reasons for revisions to GDP by Blue Book back to 1999.
Blue Book 2018
The main upward impacts on the level of GDP come from improvements to the methods used to estimate net spread earnings and gross fixed capital formation (GFCF) purchased software. The following provides more details on the individual improvements.
- Net spread earnings: this change is driven by more comprehensive coverage supplied to Office for National Statistics (ONS) from the Bank of England. This resulted in an increase in exports of services across all years as part of the supply and use framework.
- GFCF- purchased software: further changes to correct the estimation of elements of purchased software.
- Pensions: data and methods improvements to calculate figures for funded public-sector employee pensions in the financial corporation’s sector. This change was driven by the ONS Economic Statistics Classification Committee and improving the method as defined in the European System of Accounts 2010 (ESA 2010).
Full details can be found here
Blue Book 2017
Methodological improvements include actual and imputed rental, improvements to recording gross fixed capital formation as well as the separation of estimates for the households and non-profit institutions serving households sector. Other methodological improvements include unfunded public-sector pensions methodology review, improvement to illegal activities, revised estimates of exhaustiveness and concealed income adjustment, revised estimates of Value Added Tax fraud, BBC data update, and public-sector finances alignment. These improvements were driven by international transmission requirements, stakeholder interest and continuous development. The reference year moved from 2013 to 2015. This re-referencing is a part of the annual chain-linking methodology and is a standard revision for each Blue Book.
Full details can be found here.
Blue Book 2016
Methodological improvements driven by requirements under international standards, ensuring comparability in measuring gross national income across European counties and other changes to meet user needs such as imputed rental, exhaustiveness adjustments for concealed income, estimates for Value Added Tax fraud, illegal activities, own account construction, Transport for London capital stock changes, natural gas imports from Norway. Corrections made to gross fixed capital formation for improvements to dwellings and to agricultural data. The reference year moved from 2012 to 2013. Full details can be found here.
Blue Book 2015
Improvements to ESA 95 GNI reservations for exhaustiveness adjustments for concealed income and under-coverage of unincorporated businesses, new estimates within the NPISH sector and a rebalance across all sectors, cross-border property income, improvements to the estimation of spending on repairs and maintenance of dwellings by householders, improvements to the estimation of the consumption of fixed capital on roads and a change to the recording of Vehicle Registration Tax as a fee paid on a vehicle when it is first registered. These were driven by changes required by international standards and guidelines and ensuring comparability. Other improvements driven to meet user needs were related to gross fixed capital formation, reclassifications, local government pensions, alcohol and tobacco in household final consumption expenditure, narcotics, Consumer Price Index including housing (CPIH) alignment, insurance industry measurement. The reference year moved from 2011 to 2012. Full details can be found here.
Blue Book 2014
Changes were made in line with international standards adopted by all European Union (EU) member states and with worldwide best practice. Changes in the treatment of some activities (such as research and development, and military expenditure) alongside the inclusion of previously uncounted ones (such as illegal activities). Other changes included the review of public sector finances and further alignment of national accounts with public sector finances, improved methods for inventories and gross fixed capital formation, Producer Price Index (PPI) and Services Producer Price Index (SPPI) re-basing from 2005 to 2010. Reference year moved from 2010 to 2011. Full details can be found here.
Blue Book 2013
Blue Book 2013 was partly constrained by the additional time required to allow for the implementation of ESA2010 and BPM6 in Blue Book 2014. In Blue Book 2013, European System of Accounts (ESA) 95 GNI for own account software, improved estimation of artistic originals and imputed rentals of owner occupiers were all addressed back to 1990. The gross capital formation methodological development revised estimates of gross fixed capital formation (GFCF) and changes in inventories back to 1997 and improvements were made to the estimates of bonds data and overseas deposits of private non-financial corporations. Improvements were also made to the alignment of national accounts with the public-sector finances. Reference year moved from 2009 to 2010. Full details can be found here.
Blue Book 2012
Improvements were made to insurance services to ensure the methodology was compliant with ESA 95 and Eurostat Task Force guidance. The new series were fully on an accruals basis for both life and non-life insurance services, and incorporate reinsurance services for the first time. The deflator also changed from RPI to CPI pre-1997 to start of GDP series in line with Eurostat’s Price and Volume handbook. Reference year moved from 2008 to 2009. Full details can be found here.
Blue Book 2011
Blue Book 2011 was published for the first time using the revised Standard Industrial Classification 2007 (SIC07) in keeping with EU regulations. All ‘product ’outputs were also classified according to the Classification of Products by Activity 2008 (CPA08). The reference year moved from 2006 to 2008. ONS also incorporated a new processing platform CORD. Full details can be found here.
Blue Book 2010 There was little change in this release, the reference year changed from 2005 to 2005 and there was a rebalance of 2006 to 2007 with balanced 2008 for the first time. Full details can be found here.
Blue Book 2009
Following the introduction of a revised method for the allocation of ‘financial intermediation services indirectly measured’ (FISIM) in the 2008, this Blue Book included new analysis on this impact. There was a rebalance of 2004 to 2006 and balanced 2007 for first time and reference year moved from 2003 to 2005. Full details can be found here.
Blue Book 2008
Methodological improvements for the output of financial intermediation services indirectly measured (FISM) made in line with international standards adopted by all European Union (EU) member states and with worldwide best practice. For supply and use tables, there was a rebalance of 2004, with 2005 and 2006 balanced for the first time after the suspension from 2007 following modernization. Full details can be found here.
Blue Book 2007
This Blue Book was closed to all revisions to ensure resource was in place to deliver a modernized National Accounts system and methods in Blue Book 2008. This was agreed after consultation with the Bank of England and HM Treasury, that the annual updating of the GDP accounts through the Input-Output Supply and Use framework would not take place this year. Full details can be found here.
Blue Book 2006
In this Blue Book, the accounts were fully re-balanced through the Input-Output Supply and Use framework for 2003 and 2004. As part of the development of the Index of Services, methodological changes were made across a range of service industries, affecting the chained volume measures of service industries’ output. This was driven by ensuring the methodology in line with international standards adopted by all European Union (EU) member states and with worldwide best practice. The reference year changed from 2002 to 2003. Full details can be found here.
Blue Book 2005
Changes include the accounts which were fully re-balanced through the Input-Output Supply and Use framework for 2002 and 2003, and the reference year changed from 2001 to 2002. A new methodology was introduced for estimating the output of government education and social protection and an improved allocation of central government consumption expenditure to ensure that the functional breakdown correctly reflects recent machinery of government changes, to meet international standards. Full details can be found here.
Blue Book 2004
Changes include the accounts which were fully re-balanced through the Input-Output Supply and Use framework for 2001 and 2002, and the reference year changed from 2000 to 2001. There were also changes due to reclassified NHS trusts from public corporation sector to central government sector, driven by ONS Economic Statistics Classification Committee. Full details can be found here.
Blue Book 2003
Methodological improvement to the estimation of real GDP by annual chain linking. As opposed to using the constant price structure used in fixed-base chain linking to estimate GDP, the annual chain-linking process has brought about “chained volume measures”; which applies the price structure for the previous year each year and can be referenced against a base year (2000, when this method was introduced). This was driven by international standards and worldwide best practice. Full details can be found here.
Blue Book 2002
No revisions pre-1996 and very closed in terms of revisions.
Blue Book 2001
Under the ESA95 and the SNA93, estimates for tobacco and alcohol smuggling are included within the boundary of economic activity in the National Accounts. There was also improved methodology for measuring government output at constant prices as recommended by SNA93. Full details can be found here.
Blue Book 2000
New methodology was used in the calculation of capital consumption which has been taken back to 1948. Full details can be found here.
Prior to Blue Book 1999
The formats of the 1999 Blue Book and Pink Book were substantially changed in 1998 to reflect the adoption of the new European System of Accounts (ESA 1995) and the Balance of Payments Manual. Full details can be found here.
These changes followed revisions to international standards, and harmonized the statistics that the ONS publishes for international and domestic purposes. After conversion, the household, financial corporations, and overseas sectors were fully articulated in the required national accounts format from 1987, but not before.
We currently do not hold electronic records of changes in Blue Books prior to 1999. Further information, however, can be collated via paper copies of each available Blue Book from the ONS Library. To access such information please contact KIM.Team@ons.gov.uk to arrange a visit.