1. Methodology background


 National Statistic   
 Survey name  Quarterly Public Sector Employment Survey (QPSES)
 Frequency  Quarterly
 How compiled  Sample based survey
 Geographic coverage  UK
 Sample size  900
 Last revised  14 December 2016

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2. Overview

  • sample size of approximately 900 respondents
  • times series data available from 1999 on a seasonally adjusted basis, and 1991 on a non-seasonally adjusted basis
  • sample frame consists of complete coverage of local government and Civil Service and coverage of public bodies with 20 or more employees

Public Sector Employment (PSE) is a quarterly measure of the number of employees in the UK public sector. The statistics provide estimates of PSE by both government sector and industry.

In 2005, we collaborated with other government departments and the devolved administrations to implement major improvements to PSE estimates. Standard definitions for public sector employment across all departmental statistics were agreed upon, and a single definitive set of quarterly PSE estimates were introduced. A new Quarterly Public Sector Employment Survey (QPSES) was established.

PSE statistics are derived from a range of sources. The primary source is the QPSES, which collects data from local authorities in England and Wales, Civil Service departments, agencies and public bodies in Great Britain.

PSE estimates are used across government and feed into a number of wider publications and outputs. Some government departments use the total figures to facilitate policy making, whereas others use specific components of the data collection. The main users include the Cabinet Office, HM Treasury (HMT), the Scottish Government, the Department for Communities and Local Government (DCLG) and the Local Government Association (LGA).

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3. Executive summary

This report relates to the Office for National Statistics (ONS) output Public sector employment (PSE). PSE is a quarterly measure of the number of employees in the UK public sector. The series provide estimates of PSE by government sector and industry.

In 2005, ONS, in collaboration with other government departments and the devolved administrations, implemented major improvements to PSE estimates. Standard definitions for public sector employment across all departmental statistics were agreed and a single definitive set of quarterly PSE estimates introduced. A new Quarterly Public Sector Employment Survey (QPSES) was established. The QPSES collects data from local authorities in England and Wales, Civil Service departments and agencies in Great Britain and public bodies in Great Britain.

We publish official PSE estimates each quarter (3 month period) as National Statistics in the form of a statistical bulletin, approximately 11 weeks after the period to which they refer. As well as estimates of total public sector employment and private sector employment, breakdowns are published by government sector and by broad industrial classification, together with Civil Service employment by government department.

This report contains the following sections:

  • Output quality
  • About the output
  • How the output is created
  • Validation and quality assurance
  • Concepts and definitions
  • Other information
  • Sources for further information or advice
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4. Output quality

This report provides a range of information that describes the quality of the output and details any points that should be noted when using the output.

We have developed Guidelines for Measuring Statistical Quality; these are based upon the five European Statistical System (ESS) Quality Dimensions. This report addresses the quality dimensions and important quality characteristics, which are:

  • relevance
  • timeliness and punctuality
  • comparability
  • coherence
  • accuracy
  • output quality trade-offs
  • assessment of user needs and perceptions
  • accessibility and clarity

More information is provided about these quality dimensions in the following sections.

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5. About the output

Relevance

(The degree to which the statistical outputs meet users’ needs.)

Public sector employment (PSE) statistics are derived from a range of sources. The primary source is the Quarterly Public Sector Employment Survey (QPSES), which comprises three separate data collections: the home Civil Service, local authorities in England and Wales, and Great Britain public corporations and non-departmental public bodies (NDPBs).

What it measures

Employment in the UK public sector.

Frequency

Public sector employment estimates are produced on a quarterly basis.

Sample size

Approximately 900 respondents.

Periods available

Consistent time series are available back to 1999 on a seasonally adjusted basis and back to 1991 on a non- seasonally adjusted basis.

Sample frame

Complete coverage of local government and Civil Service, coverage of public bodies with 20 or more employees.

Sample design

Census.

Weighting and estimation

No weighting is undertaken on the survey estimates. Seasonal adjustment is performed on the survey estimates.

Imputation

Estimates for non-response are made using standard imputation techniques employed by Office for National Statistics (ONS) business surveys.

Outliers

No filtering of outliers.

The public sector comprises central government, local government and public corporations as defined for the UK National Accounts, which are produced by Office for National Statistics (ONS). The national accounts are compiled based on an internationally comparable accounting framework and describe the activities in a national economy. The relevant international manuals are European System of Accounts 2010: ESA 2010 and accompanying Manual on Government Deficit and Debt (MGDD). These include rules on classifying statistical units (organisations and bodies) and the transactions they engage in. A summary of these and our approach to their application, can be found on our economic statistics classification page.

The Public sector classifications guide provides information on the classification of organisations and institutions in the national accounts.

PSE estimates relate to the number of people employed according to returns from relevant organisations, however, these include a number of workers with a second job in the public sector whose main job is in the private sector or in a separate public sector organisation. The private sector estimate, which is obtained by taking the difference between the Labour Force Survey (LFS) estimate of people employed in the whole economy and the public sector total, will thus tend to be correspondingly understated by a small percentage.

Strengths and limitations

A major strength of the PSE data collection is the QPSES, which was established to fill gaps not met by other sources and improve the accuracy and coverage of estimates. When the survey was set up, it was possible to rationalise other data collections, improving consistency across government with regards to the publication of official employment statistics. The following collections were rationalised.

Mandate collection

Cabinet Office previously carried out the Mandate collection, which was sent to all Civil Service departments every 6 months, requesting a wide range of data on the department’s workforce, such as employment, earnings, diversity and regional breakdowns.

With the introduction of a quarterly employment survey, the Mandate collection became annual and in 2006 was transferred to ONS and rationalised. The annual survey is now known as the Annual Civil Service Employment Survey and still performs an important function in providing a detailed profile of the Civil Service, with the QPSES providing more timely workforce numbers. An HM Treasury survey of the Civil Service was also discontinued when QPSES was introduced.

Local authorities

QPSES replaced a long-standing quarterly ONS survey of local authorities, bringing definitions in line with the agreed standards for the public sector. Additionally, the Local Government Association (LGA) stopped their annual employment survey of local authorities in England. With written permission of the local authorities, QPSES data are now shared with the LGA.

One of the limitations of the survey is that achieving complete coverage of the public sector is extremely difficult. For instance, there is still a degree of development work to be carried out to ensure full coverage for local and central government. We have undertaken initial work to look at the reasons and extent of this under coverage. The main problem relates to local education authority (LEA) maintained schools in England, which are opting out of local authority payroll administration.

As ONS surveys ask for employees on the payroll, we know that some schools are missing from our surveys and as a result are investigating the best way to address this. At the same time we are conscious of the need to minimise the form-filling burden for schools. We continue to liaise with the LGA and local authorities on this issue. This situation has been exacerbated as a number of educational institutions have opted out of local authority payrolls as they have been certified as academies and under central government rather than local government control. We are undertaking further work with local authorities to understand better this movement of employees.

Users and uses

The PSE estimates and data produced for the quarterly publication are used across government and feed into a number of wider publications and outputs. Some government departments use the total figures to facilitate policy-making whereas others use specific components of the data collection. The main users are as follows:

  • Cabinet Office –- Civil Service statistics on a headcount and full-time equivalent basis are used to monitor changes in Civil Service numbers and form the basis for briefing the Cabinet Secretary; the statistics are used to monitor equality and diversity issues across the Civil Service

  • HM Treasury–- HM Treasury uses the statistics to answer Parliamentary Questions on PSE; the PSE statistics are used as a means of reconciliation between ONS-published data on workforce numbers that are collected by the Office for Government Commerce (OGC) to monitor progress and the 2004 Efficiency Review targets on workforce reductions

  • Scottish Government –- the headline PSE statistics are used to provide context for the Scotland PSE estimates, which are published on the same day

  • Department for Communities and Local Government (DCLG) –- the Local Government Finance team at the DCLG require local authority employment estimates to validate paybill and workforce statistics collected by Local Government Association Analysis and Research (LGAAR)

  • Local Government Association (LGA) – with the permission of the local authorities, the LGA publishes local authority employment data for England from the quarterly survey on their website, in place of conducting their own annual survey

Timeliness and punctuality

(Timeliness refers to the lapse of time between publication and the period to which the data refer. Punctuality refers to the gap between planned and actual publication dates.)

The time lag between publication and the reference period is 11 to 12 weeks.

Each quarter, any revisions to the previous quarter’s data are published. All quarterly figures are reviewed annually (September (Quarter 3)) and revised if necessary. PSE has consistently met the target publication deadlines.

For more details on related releases, the GOV.UK release calendar is available online and provides 12 months’ advanced notice of release dates. If there are any changes to the pre-announced release schedule, public attention will be drawn to the change and the reasons for the change will be explained fully at the same time, as set out in the Code of Practice for Official Statistics.

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6. How the output is created

Overview

Public sector employment (PSE) statistics are derived from a range of sources. The primary source is the Quarterly Public Sector Employment Survey (QPSES), which comprises three separate data collections: the home Civil Service, local authorities in England and Wales, and Great Britain public corporations and non-departmental public bodies (NDPBs) plus a small number of additional public sector bodies classified to central government, for example, National Audit Office and Houses of Parliament staff.

Due to the nature of the QPSES it is necessary for further information to be gathered from external sources so that total UK estimates can be derived for PSE totals.

The survey aims to achieve a complete census of the relevant sectors.

QPSES

Approximately 900 questionnaires are sent out every quarter requesting employment information. The reference date for the local authorities survey is the first Friday after the second Thursday of the last month of the calendar quarter. The reference date for the Civil Service and Public Bodies surveys is the last day of the calendar quarter.

It was agreed by the cross-departmental PSE steering group that the last day of the calendar quarter should be the default reference date; however, for well-established existing surveys (such as the local authorities survey) the reference dates should not be changed. This decision was made to maintain consistency with other ONS business surveys.

Respondents have approximately 4 weeks to complete the survey. Returned questionnaires go through a series of automated validation tests to check for completeness and consistency. More targeted selective editing was implemented into the QPSES in June (Quarter 2) 2011. This editing approach identifies potential errors in returned values that are having the greatest impact on survey estimates. Potential errors are followed up with respondents where further explanation is required.

The estimates of employment from these three surveys are compiled by summing the returns for the survey together with the imputed estimates for non-responders. The survey estimates are then combined with data returned by external sources (see next section), seasonally adjusted and published as a statistical bulletin. The statistical bulletin publishes quarterly estimates of the level of employment at a point in time from March (Quarter 1) 1999 onwards and annual estimates of the level of employment from 1991 onwards. The annual figure that is published for each series is equal to the June (Quarter 2) figure of that particular year.

Estimates of PSE are produced by sector classification (central government, local government and public corporations) and industry (education, public administration, construction, health and social care) and UK region.

External sources

The following respondents supply estimates of employment on a quarterly basis:

  • Defence Statistics, Ministry of Defence (MoD) – HM Forces statistics are produced by Defence Statistics. Estimates represent UK full-strength armed forces including full-time reserve personnel, mobilised reservists, the Gurkhas and the home service battalions of the Royal Irish Regiment

  • Department of Finance and Personnel Northern Ireland (DFPNI) – the Northern Ireland Quarterly Employment Survey (QES) provides a consistent public sector employment series back to June 1977; the QES collects information from all public sector units in Northern Ireland therefore obtaining full coverage

  • NHS workforce statistics for England, Scotland and Wales are provided quarterly, for England by NHS Digital, for Scotland by the Scottish Government and for Wales by NHS Wales Informatics Service (NWIS)

  • Home Office – police workforce estimates (including special constables) for England and Wales are published every 6 months (for 2 quarters) by the Home Office; the quarterly estimates provided are therefore based on projections and may be subject to revisions when new data are published

  • Scottish Government – the quarterly Joint Staffing Watch (JSW) Survey provides the local authority figures for Scotland

  • the list of all open academies and annual School Workforce Census, published by the Department for Education (DfE) are used to estimate employment at academies each quarter.

In addition to these, the Homes and Communities Agency (HCA) provide employment data, on an annual basis, for private registered providers of social housing in England.

Seasonal adjustment

Seasonal adjustment is the process of removing variations associated with the time of the year or the arrangement of the calendar from a time series, to give a clearer picture of what is going on over time.

Seasonal adjustment was introduced to PSE for the first time during Quarter 3 2006. This brought about a significant improvement to the PSE estimates as it served to bring quarterly comparisons into line with other ONS outputs. In general it was found that where the headcount version of a series was seasonal, so too was the full-time equivalent version.

The seasonal adjustment of PSE is reviewed by ONS Methodology Directorate in October each year.

Statistical disclosure control

Statistical disclosure control methodology is applied to PSE data. The Code of Practice for Official Statistics and specifically the Principle on Confidentiality set out practices for how we protect data from being disclosed. The Principle includes the statement that our outputs should “ensure that official statistics do not reveal the identity of an individual or organisation, or any private information relating to them, taking into account other relevant sources of information”. Information attributable to individual organisations is published in some PSE outputs by prior consent. More information can be found in National Statistician’s Guidance: Confidentiality of Official Statistics.

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7. Validation and quality assurance

Accuracy

(The degree of closeness between an estimate and the true value.)

Public sector employment (PSE) estimates are based on a complete census of local government and Civil Service and cover all public bodies with 20 or more employees. The usual sampling and estimation techniques employed by Office for National Statistics (ONS) business surveys are therefore not applicable (for instance, it is not applicable for sampling errors or confidence intervals to be produced).

The published estimates are seen as being the most accurate representation of PSE within the UK.

Our targets for response to the Local Authorities and Public Bodies Quarterly Public Sector Employment Survey (QPSES) before the results are compiled are 90% (number of respondents) and 90% (of total employment). In addition, each survey has a list of critical respondents (usually those with the largest employment) for which special efforts are made to achieve 100% response and clearance of test failures. For the Civil Service QPSES the targets for response before the results are complied are 100% (number of respondents) and 100% (of total employment).

Data for non-responders are imputed based on previous returns and known annual changes in seasonality. It is extremely rare for a local authority, public body or Civil Service department to non-respond for 2 consecutive quarters. The data collection is statutory for local authorities and public bodies (Statistics of Trade Act 1947) and positive action is taken to address non-response issues as and when they occur.

Non-sampling error

Non-sampling error, or bias, is the variation that occurs by chance from the true values for the population and is not due to sampling. This type of error averages close to zero over a large number of repeats of the survey.

Response rates are monitored closely each quarter by the survey team.

Under-coverage

Three sources of known under-coverage impact on the overall PSE estimates.

First, an issue with the local authority collection relates to local education authority (LEA)-maintained schools in England and Wales opting out of local authority payroll administration. As a result they are not included in the data collected.

A second issue with the local authority collection is with schools in England adopting academy status. Such schools are classified as central government and data are collected from them separately. During the transition, there is the potential for under-counting or double-counting. In addition, local authorities may continue to operate payrolls on behalf of academies, creating the potential for misclassification. There are currently over 5,000 academies across England.

Third, PSE has known under-coverage as part of its survey of public bodies; public bodies with less than 20 employees are not surveyed. The level is approximately 500 people and this is not considered to affect the overall survey estimates.

In the event of a large error being detected in the data, the overview report and datasets will be revised in line with the Code of Practice for Official Statistics. More information on revisions can be found in National Statisticians Guidance: Presentation and Publication of Statistics and the ONS Guide to statistical revisions.

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8. Coherence and comparability

(Coherence is the degree to which data that are derived from different sources or methods, but refer to the same topic, are similar. Comparability is the degree to which data can be compared over time and domain, such as geographic level.)

Earlier time series

Time series are available back to 1999 on a seasonally adjusted basis and back to 1991 on a non-seasonally adjusted basis. Because of the nature of the data collection and the movement from an annual to quarterly collection, it was only possible to take the method of seasonal adjustment back to the start of the quarterly series in 1999. For earlier estimates (which are on a different basis) users should consult Labour Market Trends Volume 112, Number 7) article Jobs in the Public Sector mid-2003.

Cabinet Office

Cabinet Office publishes an annual Public Bodies Directory but this does not provide the coverage or timeliness of the PSE quarterly survey. They also take monthly and quarterly data collections of management information from Civil Service departments and agencies and non-departmental public bodies (NDPBs). This information is used to help quality assure the quarterly PSE estimates.

Education

The estimates of PSE in education (Standard Industrial Classification (SIC) division 85) differ from the school workforce estimates published by the Department for Education (DfE) mainly as a result of differences in coverage and data sources.  

DfE estimates focus on the number of full-time equivalent teachers and support staff for England only. By comparison, the ONS estimates are derived by allocating local authority employees to education using the Inter-Departmental Business Register (IDBR) and the QPSES in England and Wales.

The DfE School Workforce Census school level estimates are used to estimate employment in academies in England. PSE estimates include all employees reported by local authorities as working in primary, secondary and adult education establishments including some groups who are not covered by the DfE statistics, such as adult education staff and certain categories of support staff. Employment estimates for education in Scotland and Northern Ireland are also included to give a wider UK coverage. The different coverage of the ONS and DfE education statistics serve the needs of different users.

Those who require information on the workforce in England who are directly involved in pupils' teaching and learning should use DfE published statistics. You should also refer to DfE published statistics to gauge trends in education employment. Those who seek data on UK PSE in education, in its widest sense, should use the ONS data in this release.

National Health Service (NHS)

ONS estimates for the NHS also differ from the headline figure produced by NHS Digital. Again, this reflects the wider UK coverage (NHS Digital figures are for England only) plus our exclusion of general practitioners (GPs). In accordance with national accounts practice, we classify GPs as part of the private sector. When these factors are allowed for, ONS and NHS data can be shown to be identical.

Labour Force Survey (LFS)

The figures published in the PSE statistical bulletin are the best estimates of PSE and are in line with national accounting principles. They are based on administrative records and surveys of public sector organisations.

In contrast, while the LFS provides the UK’s primary measure of the number of people in employment as a whole, it does not provide a fully reliable measure of the total number of employees in the public sector. This is because the LFS is a social survey, based on responses and self-classification from individuals in private households. It is widely acknowledged that when interviewed for the LFS, individuals incorrectly classify themselves as working in the public sector. For example, employees of bodies such as universities frequently incorrectly classify themselves as being in the public sector. Universities are, in fact, part of the private sector according to national accounts definitions. Similarly, employees of private sector companies providing contracted out services to the public sector can also incorrectly classify themselves as public sector employees.

The LFS thus overestimates public sector employment (the LFS estimate is currently around 1 million higher) and the difference tends to vary over time.

Sector classification

The national accounts provide a framework for describing what is happening in national economies. All institutional units operating within an economy are classified to an institutional sector and all transactions between the sectors of the economy are categorised. Work on the classification of entities to sectors and of economic transactions is an important input in the production of national accounts and employment figures alike.

Changes to the classification of individual institutional units, known as reclassification, can have a noticeable effect on employment statistics at a sector level. It is vitally important that users of PSE estimates are aware of reclassifications as and when they occur. Although reclassifications of institutional units are infrequent they can have a significant effect on employment estimates on a quarterly basis.

Users should check to ensure that, when comparing quarterly and annual figures, the figures they are comparing are directly comparable and have not been influenced by a large-scale reclassification. The PSE statistical bulletin strives to keep users updated with all current movements and how they have been incorporated within the published estimates. We produce series of public and private sector employment excluding the effects of major reclassifications, to help users understand underlying trends in employment.

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9. Concepts and definitions

(Concepts and definitions describe the legislation governing the output and a description of the classifications used in the output.)

Central government includes all administrative departments of government and other central agencies and non-departmental public bodies (NDPBs); as such it is wider than the “Civil Service”. This sector also includes HM Forces and the NHS. Within education, academies are classified to central government. From 1 April 2005, central government includes the former Magistrates' Courts Service, which has been brought together with the Court Service to form Her Majesty's Courts Service. The Magistrates' Courts Service was previously classified to local government. It also includes the British Transport Police in England and Wales and, from June 2013, the Police Service of Scotland.

Local government covers those types of public administration that only cover a locality and any bodies controlled and mainly financed by them. The sub-sector includes all areas of administrative authorities including parish councils, though these units are not covered by the current estimates for local authorities. It includes police forces and their civilian staff for England and Wales, excluding the British Transport Police. Until June 2013 it included the Police Service of Scotland.

All functions of local authorities are classified to the sub-sector, although trading activities that produce market output (for example, housing and municipally-owned markets) are regarded as quasi-corporations and appear under public corporations. Local education authorities are part of local government, as are voluntary-aided schools, county schools and, from September 1999, foundation schools (formerly grant-maintained).

Public corporations are companies or quasi-corporations controlled by government, for example, London Underground Ltd. These companies receive more than half their income from sales of goods or services into the marketplace.

The estimates of Civil Service employees count all home Civil Service employees and can be classified to central government or public corporations. Examples of public corporations include the UK Intellectual Property Office and the Driver and Vehicle Standards Agency. Civil Service estimates exclude the Northern Ireland Civil Service and other Crown servants. Employees in these groups are included in estimates of central government employment.

Headcount estimates are based on the number of employees with an employment contract who are being paid by the organisation. Employees can be permanent, on a fixed-term contract or employed on a casual basis. Self-employed, contract workers and agency workers are excluded.

Full-time equivalents are based on converting part-time employees’ hours to full-time employees’ equivalent and provide a better indication of total labour input than a simple headcount. Estimates are produced back to 1999.

Permanent employees are those with a contract with no agreed expiry date, or a fixed term contract of more than 12 months.

Temporary or casual employees are those with a fixed-term contract of 12 months or less, or employed on a casual basis.

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10. Other information

Output quality trade-offs

(Trade-offs are the extent to which different dimensions of quality are balanced against each other.)

For later periods, estimates of public sector employment (PSE) are based partly on projections for some sources. As part of the development programme to improve the quality of PSE estimates, public sector organisations are working towards the production of timely quarterly estimates. Until this development programme is completed, there remains a requirement to include estimates for certain sources.

Police workforce estimates (including special constables) for England and Wales are published every 6 months (for 2 quarters) by the Home Office. These quarterly estimates are therefore based on projections, and may be subject to revisions when new data are published.

NHS workforce statistics for England are derived from a pay system which covers all but two English NHS organisations. This produces very good estimates of staff numbers. Figures for the two other organisations are estimated based on quarterly NHS workforce figures.

Annual employment data for private registered providers (PRPs) of social housing (referred to as housing associations in the PSE statistical bulletin and associated datasets) in England are provided by the Homes and Communities Agency (HCA); a quarterly time series has been derived from this. To give timely estimates each quarter, a forecast has been provided by the ONS Methodology Directorate. Therefore the series may require revisions when new annual data are available. The HCA employment data only covers the large PRPs and therefore an adjustment is made to the data to account for the smaller PRPs.

Revisions to take account of late information from respondents and seasonal adjustment updates are made in accordance with the published revisions policy.

Assessment of user needs and perceptions

(The processes for finding out about users and uses, and their views on the statistical products.)

The Prime Minister’s instruction on the Control of Statistical Surveys requires regular surveys to businesses and local authorities to be reviewed at least once every 3 years.

A Triennial Review of PSE was carried out in January 2008.

An additional review of PSE was undertaken at the end of 2010.

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11. Sources for further information or advice

Accessibility and clarity

(Accessibility is the ease with which users are able to access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the release details, illustrations and accompanying advice.)

Our recommended format for accessible content is a combination of HTML webpages for narrative, charts and graphs, with data being provided in usable formats such as CSV and Excel. Our website also offers users the option to download the narrative in PDF format. In some instances other software may be used, or may be available on request. Available formats for content published on our website but not produced by us, or referenced on our website but stored elsewhere, may vary. For further information please refer to the contact details at the beginning of this report.

For information regarding conditions of access to data, please refer to the following links:

In addition to this Quality and Methodology Information, quality information relevant to each release is available in the quality and methodology section of the relevant statistical bulletin.

Useful links

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Contact details for this Methodology

Debra Leaker
pse@ons.gsi.gov.uk
Telephone: +44 (0)1633 455874