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Following the release of publicly available data in July 2014, four safeguarded tables on migration in England and Wales, and equivalent four tables for Northern Ireland, will be available shortly:

  • total flows for the OA hierarchies and cross tabulations by broad grouped age and sex for the ward hierarchies.

UK versions, and a subset of the travel to work safeguarded UK tables, will follow soon.

The proposed release timetable for the remaining origin-destination products is:

  • November 2014 - secure files  available in tranches, and

  • December 2014 -  safeguarded files available in tranches

These dates are not yet confirmed and are subject to change. It is expected that all of the publicly available tables will have been included in the July release, (apart from those affected by a Scottish data issue which will be released as soon as possible). Until tables have been through statistical disclosure control checks the release channel cannot be confirmed. ONS has an obligation to protect the attributes of identified individuals and may revise table designs prior to release if they are deemed to be disclosive on completion.

Data analysts can apply to ONS and register with UK Data Services to access this first tranche of safeguarded origin-destination tables.

About the data

Origin-destination tables comprise the travel-to-work and migration patterns of individuals, cross-tabulated by variables of interest (for example occupation). New products for the 2011 Census provide the migration patterns of those living at a student address one year ago and provide information on individuals with second residences.

The UK Statistical Disclosure Control policy states that additional protection of the most detailed origin-destination tables comes from the licensing/access conditions. This is a change from the 2001 Census, where the protection for similar outputs came from the post-tabular small cell adjustment which still allowed wide and easy access, but also affected the usefulness of the outputs.

The 2011 Census origin-destination tables are classified in three ways:

  • Public tables available under Open Government Licence via the ONS website,

  • Tables with slightly more detail not available to the public are termed safeguarded and can only be accessed by data analysts under terms and conditions,

  • Tables with greater detail are termed secure and are only accessible in the ONS Virtual Microdata Laboratory.

For more information on the statistical disclosure control policy for origin-destination tables, please read section 8 of the Statistical disclosure control for 2011 Census.

Flow data table layouts for origin-destination tables. These specifications confirm the geographies for each table, and a provisional indication of the classification of each table - public, safeguarded or secure. Each dataset will be assessed for disclosure before a final decision on the access channel is made. Some of the tables indicated as secure may be available via the safeguarded channel.

A large amount of the origin-destination specifications are at UK level, providing flows for usual residents of England, Wales, Scotland, and Northern Ireland. Any statistics not easily harmonised across the UK due to differences in the data collected are provided for usual residents of England and Wales only. These statistics still provide geographical detail of flows between the other countries of the UK. 

First versions of some safeguarded and secure tables will be provided for England, Wales and Northern Ireland. United Kingdom results will be published later in the year when the issue with Scottish data has been resolved. These versions will provide statistics for England and Wales in separate tables to the statistics for Northern Ireland. The issue found with the Scottish results also affects the European Commission Census Regulation Statistics which were released in March 2014, and the planned release of migration statistics for the UK.

Travel-to-work data for England and Wales use workplace zone geography to show flows between output areas of usual residence to workplace zones.

Access to tables

Public tables

Access to most tables is restricted, but a small number of tables are already available to everyone via nomis.

The first batch of origin-destination tables was released on 25th July 2014. There were two releases:

  1. Origin-destination statistics on migration, workplace and students for local authorities in the United Kingdom, and

  2. Origin-destination statistics on second residences and workplace for merged local authorities and middle layer super output areas (MSOAs) in England and Wales.

The UK release consists of 11 tables (52 Kb Excel sheet) , at local authority level. The scope of this release changed from that previously announced, with only the three workplace tables covering the whole of the UK. The other four pre-announced tables covering migration and students, are available for England and Wales and Northern Ireland only, and do not cover the whole of the UK.

National Records of Scotland, responsible for the 2011 Census in Scotland, has identified an issue with the Scottish results that needs resolving before the data can be published. A release date for UK tables will be published on this page.

Statistics for England and Wales are provided in separate tables to those for Northern Ireland, giving a total of eight tables rather than four as announced. 

The England and Wales release consists of nine tables (47.5 Kb Excel sheet) , six at local authority level and three at middle layer super output area (MSOA) level. This release was not affected by the issue with the Scottish results, and was published as originally planned.

Safeguarded tables

These are more detailed tables and will only be accessible under terms and conditions. Safeguarded tables (35.5 Kb Excel sheet)  are being released from October 2014. These tables will not be in the public domain with equal access to all. Release dates for these tables will be published on this page, not announced in the ONS Release Calendar. Please note that as statistical disclosure control checks are still being carried out on these tables, we cannot confirm that all these tables will be released as safeguarded data. 

Access to these tables will be via services provided by ONS and UK Data Service. Different access arrangements are needed to maintain public confidence in how ONS protects confidentiality of data while providing access to a wide range of users.

Access in the ONS VML

Researchers will be able to access safeguarded 2011 Census tables and historical census microdata within the ONS Virtual Microdata Laboratory based in the ONS London office. Similar terms and conditions to those of the UK Data Service will be applied. Special application procedures, approval processes, and disclosure checks on output will apply. There will be no requirement for researchers to apply for the status of approved researchers.

Researchers can now request access to the ONS VML by emailing the VML admin team at VML.Service.Desk@ons.gsi.gov.uk. Researchers will be issued with a Data Access Agreement for signature and return. A VML account will be set up on application approval and the researcher will be invited to attend a mandatory security briefing and training session. Applications will normally be processed, and a date offered within two weeks of submission.

A date and time for a research session will be offered, usually on the same day as the training. As users of safeguarded data cannot be in the VML alongside approved researchers, dedicated sessions for safeguarded users can only be held on Mondays. It is expected that the first session will be held on Monday 27th October, subject to demand.

The outputs generated by research in the VML will be supplied to the researcher on request. ONS, NISRA and NRS as appropriate, will conduct checks to ensure that the outputs are within the scope of the project and that it is not possible to reproduce the raw data from them.

Access via UK Data Services

The safeguarded tables will be available shortly to academic and public sector researchers through the Web-based Interface to Census Interaction Data (WICID) system; a flexible interface providing access to origin destination (flow) data that is provided by the UK Data Service. Researchers wishing to use the UK Data Service will need to register and accept terms and conditions before accessing and downloading data through WICID.    

All members of UK Higher Education (HE) belong to the UK Access Federation and these credentials enable access to the UK Data Service by academic researchers in HE. Public sector users need to obtain a UK Data Archive username and password (external link) and then use these to register with the UK Data Service.
 
All users must agree to the terms and conditions of the UK Data Service End User Licence before data can be accessed and downloaded.  

Find out how to register and information on how to access the origin destination data in WICID.

Secure tables

The most detailed tables are secure tables (44 Kb Excel sheet) and will only be available within a secure ONS environment. In the long term, a complete set of origin-destination data will be held in a new ONS Virtual Microdata Laboratory (VML) currently in development. To provide access to the first tranche of secure tables, ONS has constructed a VML at Titchfield as an interim measure from November 2014.  As with the safeguarded tables, release dates will be published on this page not in the ONS Release Calendar.

ONS will not accept any requests for access to this data before November. The approval process to gain access to the secure data in the VML will take approximately two to three weeks.
Secure census data in an ONS VML will only be available to approved researchers. Read about how to be accepted as an approved researcher.

Summary

The table below summarises how the safeguarded and secure data will be available to different types of users.

Safeguarded data Secure data
Academics

UK Data Service

VML London

(Approved Researcher status not required)

VML Titchfield

Other ONS locations when new VML in place

(Approved Researcher status required)

Government and public sector

UK Data Service

VML London

(Approved Researcher status not required)

VML Titchfield

Other ONS locations when new VML in place

(Approved Researcher status required)

Commercial organisations

VML London

(Approved Researcher status not required)

VML Titchfield

Other ONS locations when new VML in place

(Approved Researcher status required)

Other

VML London

(Approved Researcher status not required)

VML Titchfield

Other ONS locations when new VML in place

(Approved Researcher status required)

 
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