1. Methodology background


 National Statistic   
 Survey name  Local area migration indicators suite QMI
 Frequency  Annual
 How compiled  Based on third party data
 Geographic coverage  England, Wales, Scotland and Northern Ireland
 Last revised  24 August 2017

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2. Important points about Local Area Migration Indicators Suite data

  • Each indicator in the Local Area Migration Indicators Suite provides different measures; together these can provide a more complete picture of migration in local areas.
  • The indicators used in the suite are from various data sources, which use different definitions and count different types of migration; this should be taken into consideration when comparing the data.
  • The suite contains complete information for the years 2005 to 2016 (except for Short-Term International Migration, which are available to mid-2015 and Northern Irish data, which are available to mid-2014).
  • The migration data, migrant GP registrations and National Insurance number (NINo) allocations to overseas nationals can be used for indications of the ”flows” of migrants into and out of geographical areas.
  • The non-UK born population, the non-British nationality population and the live births to non-UK born mothers data give an indication of the “stock” of migrants living in the UK.
  • Figures are shown for 406 local and unitary authorities (348 in England and Wales, 32 in Scotland and 11 (known as LGD2014) in Northern Ireland, except for NINo registrations, where there are still 26 codes (known as LGD1992), 33 counties, nine regions and the four countries of the UK.
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3. Overview of the output

The Local Area Migration Indicators Suite is an annual publication, released every August and contains Llong-Term International and internal and Short-Term International Migration statistics, non-UK born population statistics, non-British nationality population statistics, migrant General Practitioner (GP) registration counts, migrant National Insurance number (NINo) allocations and live births to non-UK born mothers statistics.

The Local Area Migration Indicators Suite is an Excel spreadsheet, which allows access for the user’s own analysis to the underlying data containing all indicators for all available geographies. Most of the data included in the suite are published elsewhere; this product adds value by bringing migration-related statistics together in one place to enable comparisons to be made more easily.

The Migration Indicator Tool enables comparison of data published by Office for National Statistics (ONS), National Records of Scotland (NRS), Northern Ireland Statistics and Research Agency (NISRA), Department for Work and Pensions (DWP) and Patient Register Data Service (PRDS) to gain an indication of migration at local level.

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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 these quality dimensions and other important quality characteristics, which are:

  • relevance
  • timeliness and punctuality
  • coherence and comparability
  • 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.)

The Local Area Migration Indicators Suite provides migration-related information for local areas. Most of the data included in the suite are also published elsewhere – the added value of this product is that migration-related statistics are brought together in one place, enabling comparisons to be made more easily. Each indicator provides different measures, which together can provide a more complete picture of migration in local areas.

The suite includes migrant stock estimates of the non-UK born and non-British nationals. These are not estimates of recent migration into an area, but they are associated with migration flows. For example, areas with high proportions of the population born outside of the UK are likely to also have high levels of migration.

The indicator suite is an Excel spreadsheet, which allows users to compare up to three geographical areas for a selected indicator, or to compare up to three indicators for a selected geography. The suite also allows access to the underlying data containing all indicators for all available geographies for the user’s own analysis. It should be noted that not all indicators are directly comparable (for example, some are flows (movement into and out of an area) and some are stocks (the resident population of an area)). The geographic coverage also varies.

The following data are included within the suite.

Migration flows

Long-Term International and internal migration estimates at local authority level for England, Wales, Scotland and Northern Ireland are produced by Office for National Statistics (ONS), National Records of Scotland (NRS) and Northern Ireland Statistics and Research Agency (NISRA) for the purpose of producing population estimates. The data are presented as follows:

  • long-term international immigration and emigration volumes – representing the number of people arriving in the UK or leaving the UK for a period of at least 12 months
  • internal in-migration and out-migration volumes –- an estimate of migration within the UK (cross-border flows between each of the constituent countries, as well as migration between local authorities)
  • long-term international and internal migration turnover rates (such as volume of movement between in- and out-migration) per 1,000 (of the total population)
  • long-term international inflow and outflow rates per 1,000 (of the total population)
  • total volume of migration per 1,000 (the sum of internal and international migration); this indicates more clearly the areas with high levels of population turnover

Short-Term International Migration estimates at local authority level for England and Wales are produced by ONS. The data are presented as follows:

  • short-term international immigration volumes – representing the number of people who stayed in England and Wales for a period between 3 and 12 months

Non-UK born population and non-British nationality population

Estimates of the non-UK born and non-British nationality populations covering the UK are estimated by ONS using the Annual Population Survey (APS). The APS has the largest coverage of any ONS household survey and is an indicator of migration stocks.

The survey covers private households but most communal establishments are excluded. Students living in halls of residence will be captured by proxy, but only if they have a UK resident parent. This means most international students living in halls of residence will not be identified in the APS.

In March 2015, the APS was reweighted using revised UK and subnational population estimates consistent with the 2011 Census. In July 2015, we published reweighted estimates of the UK population by country of birth and nationality for calendar years 2004 to 2013. A comparisons paper has been written looking at the differences between the old estimates and the reweighted estimates. The reweighting caused the estimate of the population of the UK to increase by 538,000 between 2004 and 2013.

Migrant GP registrations for England and Wales, and Northern Ireland

For England and Wales, each year, ONS receives a demographic snapshot of the Patient Register Data Service (PRDS) held by NHS Digital. Flag 4s are codes within the PRDS system that indicate that an individual’s last address (as registered with an NHS GP) was overseas.

For Northern Ireland, each year, NISRA receives individual code 4 (NISRA flag 4 equivalent) registrations by date of registration from the Health and Social Care (HSC) Business Services Organisation (BSO).

Migrant National Insurance number allocations

Statistics for National Insurance number (NINo) allocations to adult overseas nationals are provided by DWP. This records non-UK nationals who are legally employed (including the self-employed and students working part-time) and those wanting to claim benefits or tax credits.

Live births to non-UK born mothers

Birth statistics present data on births that occur and are then registered in England, Wales, Scotland and Northern Ireland. Statistics are based on information collected at birth registration.

Annual birth outputs represent births occurring in England, Wales, Scotland and Northern Ireland in a given year.

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 Local Area Migration Indicators Suite contains complete information for the years 2005 to 2016 (except for Short-Term International Migration, which is available to mid-2013). Figures are shown for 406 local and unitary authorities (348 in England and Wales, 32 in Scotland and 11 (known as LGD2014) in Northern Ireland, except for NINo registrations, where there are still 26 codes (known as LGD1992), 33 counties, nine regions and the four countries of the UK.

The suite was updated quarterly, with the most up-to-date data available, until August 2012. Following a consultation exercise, it was agreed to move the suite to an annual publication.

For more details on related releases, the GOV.UK release calendar provides 12 months advance 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

The Local Area Migration Indicators Suite is a compilation of various data sources. For more information on the methodology of each of the individual sources, see the following links:

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7. Validation and quality assurance

Accuracy

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

Administrative sources are not primarily designed to measure population or migration. For example, migrant GP registrations by local authority and National Insurance number (NINo) counts are all derived from administrative data sources. The coverage of international migrants joining an administrative source will depend on the purpose of the particular administrative system and will invariably differ between sources. Please see A summary of administrative data sources and their potential to inform statistics on migration and population for further details on their use.

Migration flows

The mid-year population estimates include both internal and Long-Term International Migration as components of change. There are different factors affecting accuracy for each component since each is produced using different sources and methods. The following guides provide further information on factors affecting accuracy of our migration data:

Short-Term International Migration methodology can also be accessed for further information:

Non-UK born population and non-British nationality population

The Annual Population Survey (APS) is used to estimate the household population of the UK by country of birth and nationality. These estimates are published alongside confidence intervals, detailing how accurate the estimate is by giving a range of values that the actual figure may fall between.

The APS, (Labour Force Survey (LFS) plus various local area sample ”boosts” to increase the sample size) ensures minimum representation of each area of the UK in the sample. Boost interviews are conducted throughout the year and included in the APS dataset in the quarter in which they are conducted. Respondents in the LFS boost are interviewed only once a year, for 4 consecutive years. Only in the main LFS do interviews take place each quarter.

Each quarter’s LFS sample of 40,000 households is made up from five ”waves”, each of approximately 8,000 households. Each wave is interviewed in 5 successive quarters, such that in any 1 quarter, one wave will be receiving their first interview, one wave their second and so on, with one wave receiving their fifth and final interview. Thus, there is an 80% overlap in the samples for each successive quarter and the sample is completely different after 6 quarters.

The APS combines results from the LFS and the English, Welsh and Scottish Labour Force Survey sample boosts. During 2004 and 2005, the APS also included an additional sample boost for England. Northern Ireland does not have an additional boost. More robust estimates are available by using the APS than from the main LFS. APS datasets are produced quarterly with each dataset containing 12 months of data. There are approximately 320,000 persons per dataset. For more information please see the APS Quality and Methodology Information.

The population figures used to weight the APS are adjusted to cover the same private household population that the survey covers and so differ from the mid-year population estimates. Further information can be found in the LFS user guide.

Migrant GP registrations for England and Wales, and Northern Ireland

Flag 4 counts for England and Wales, and code 4 counts for Northern Ireland, provide an indication of recent international immigration to local authority areas. However, there are a number of reasons why there may be differences with actual levels of immigration.

GP registration is not compulsory and some migrants will only register with a GP if and when they require medical attention.

Registration patterns vary by sex and age group. In particular, young males are known to be less likely to register than other groups, thus limiting the usefulness of Flag 4s as an indicator of migration. We have undertaken research on the time lag differences between groups.

A person may register with a GP if they are staying in the UK for at least 3 months and so Flag 4s may include some short-term migrants, which are not included in the population estimates (in Northern Ireland the migrants have to be staying the greater part of a year to qualify for registering with a GP, so have to be here at least 6 months and a day).

There may also be a lag between the migration event and the eventual GP registration. Flag 4 records may not be retained on patient register records through the person’s subsequent migration within the UK. When an immigrant subsequently moves internally within the UK and re-registers with a second GP, the Flag 4 record is not retained as the individual’s last residence is now within the UK. If this internal migration happens within a year of the migrant arriving in the UK, the Flag 4 will not be recorded on the extract provided to us. However, Northern Ireland still hold data for all migrants; due to the land border with the rest of Ireland Business Services Organisation (BSO) assess the right to entitlement for all patients registering, even if they are migrants registered elsewhere in the UK first.

Patients in Northern Ireland who are here on time-limiting visas are contacted 3 months before their visa is due to expire, informing them that if a new visa is not provided they will be deducted. If they provide a copy of their new visa their registration is extended, otherwise they are deducted from the GP’s register.

Northern Ireland also registers a small number of cross-bBorder workers as Code 4s as, if a person lives in the south of Ireland and works in the north then they are entitled to NHS treatment.

National Insurance number allocations to overseas nationals

A NINo is required for anyone wanting to work legally or claim benefits in the UK. Therefore, NINo allocations to foreign nationals provide an indicator of recent migration to the UK. There is no minimum stay requirement to register for a NINo, so NINo data contain both short- and long-term migrants. Migrant groups not covered by migrant NINo data include child migrants (those under 15 years 9 months), migrants who work illegally and adult migrants who neither work nor claim benefits (often students or spouses of employed migrants). Asylum seekers are also generally excluded as NINo applications are not usually approved until rights to reside in the UK have been granted.

Live births to non-UK born mothers

Birth statistics are based on registrations provided by the General Register Office (GRO). These data represent the legal record, making it the best and most complete data source.

As part of the birth registration process, the registrar asks the informant to verify that all data entered are accurate. The registrar is then able to correct any errors.

Information supplied at birth registration is generally believed to be correct, since wilfully supplying false information may render the informant liable to prosecution for perjury.

When we receive birth registrations, a number of checks are carried out on records to ensure that they are valid. Any birth records that appear questionable are raised with GRO on a monthly basis for further investigation. Further information can be found in the Birth statistics quality and methodology paper.

Coherence and comparability

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

There are other additional data sources and databases available that may provide information on movements into the UK. These sources may serve as further references on the topic. A reconciliation exercise was undertaken by us for the mid-years 2004 and 2005 and the calendar years 2003, 2004 and 2005. This exercise compared three important administrative sources (Flag 4 counts, NINo allocations, and the Workers’ Registration Scheme) with International Passenger Survey (IPS) based estimates of both Long- and Short-Term International Migration. The conclusion was that IPS-based estimates are broadly comparable with administrative sources.

The indicators used in the suite are from various data sources, which use different definitions and count different types of migration. Care needs to be taken when comparing the data. The migration data, migrant GP registrations and NINo allocations to overseas nationals can be used for indications of the ”flows” of migrants into and out of geographical areas. The non-UK born population, the non-British nationality population and live births to non-UK born mothers data give an indication of the stock of migrants living in the UK.

There are definitional differences between the data sources. For example, migrant GP registrations, NINo allocation statistics and live births data are based on administrative data sources and the coverage and measurement of international migrants will relate to what is required for administrative purposes. For example, migrant GP registrations cover nationals of all countries. For more information on administrative data and their uses, please see the Metadata and background information.

There are also differences in geographical coverage, which limits comparability:

  • Long-Term International Migration flows – England, Wales, Scotland and Northern Ireland
  • Short-Term International Migration flows – England and Wales
  • non-UK born and non-British – England, Wales and Scotland
  • migrant GP data – England, Wales and Northern Ireland
  • NINo data – England, Wales, Scotland and Northern Ireland
  • live births to non-UK born mothers – England, Wales, Scotland and Northern Ireland

The methodology that is used to update population estimates accounts for flows of Long-Term International Migration; whereas the administrative sources may include both short- and long-term migrants.

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8. Concepts and definitions

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

Migration flows

Figures presented show the volume of long-term international or internal movement and are calculated as the sum of in- and out-migration (in the year to June) per 1,000 resident population.

For Long-Term International Migration, the UN recommended definition is used: “A long-term international migrant is defined as a person who moves to a country other than that of his or her usual residence for a period of at least a year, so that the country of destination effectively becomes his or her new country of usual residence.”

Inflow

Long-term: persons arriving or returning from abroad to take up residence in a country for a period of at least 12 months.

Outflow

Long-term: persons leaving their country of usual residence to take up residence in another country for a period of at least 12 months.

Internal migration

At the national level, this component estimates migration between each of the UK constituent countries. At subnational level, estimates of flows between each local authority and other local authorities in the UK are also included. Since internal moves are not recorded formally, information obtained from the NHS Central Register (NHSCR) and GP patient registers is used as a proxy.

For England and Wales estimates, these data are considered to be a good proxy for internal migration as, when moving, most patients will eventually register with a new GP. Complete information on all moves at former health authority level from the NHSCR are combined with more geographically detailed data from the patient registers to produce the migration estimates by local authority used in the population estimates.

Short-term migration flows

Figures presented show the number of short-term international migrants who stayed in England and Wales (in the year to June) per 1,000 resident population.

The UN definition of a short-term international migrant is used: “A person who moves to a country other than that of his or her usual residence for a period of at least 3 months but less than a year (12 months) except in cases where the movement to that country is for purposes of recreation, holiday, visits to friends and relatives, business, medical treatment or religious pilgrimage.”

Short-term migration inflow is defined as: “Persons arriving or returning from abroad to take up residence in a country for a period between 1 month and 12 months”.

Non-UK born population and non-British nationality population

Figures presented show the estimated non-UK born and non-British national population living in the UK in a calendar year per 1,000 Annual Population Survey (APS) resident population.

The estimated resident population of an area includes all people who usually live there, whatever their nationality. Members of UK and non-UK armed forces stationed in the UK are included and UK forces stationed outside the UK are excluded. Students are taken to be resident at their term-time address.

Migrant GP registrations for England and Wales

Figures presented show the number of new Flag 4 records added in the previous 12 months existing on the Patient Register as at 31 July, for England and Wales per 1,000 resident population. Equivalent figures (Code 4) are provided for Northern Ireland.

Flag 4 records are provided to the Office for National Statistics (ONS) from the Patient Register Data Service (PRDS) data provided by NHS Digital. Flag 4s are codes within the PRDS system that indicate that someone has registered with a GP in England and Wales and was previously living overseas. A Flag 4 may be generated when an individual registers with an NHS GP if:

  • an individual was born outside the UK and enters England and Wales for the first time and registers with a NHS GP
  • an individual’s registration will also generate a Flag 4 if the previous address of an individual is reported as outside of the UK

Code 4 records are provided to NISRA by the Health and Social Care (HSC) Business Services Organisation. Code 4s relate to individual registrations with a GP in Northern Ireland from persons who were previously living overseas. A Code 4 may be generated when an individual registers with a NHS GP if:

  • an individual was born outside the UK and enters Northern Ireland for the first time and registers with a NHS GP
  • an individual’s registration may also generate a Code 4 if their previous address is outside the UK and they have been living outside the UK for more than 1 year

National Insurance number allocations to overseas nationals

Figures presented show the number of National Insurance number (NINo) allocations to overseas nationals entering the UK per 1,000 resident population aged 16 to 64 by calendar year.

Live births to non-UK born mothers

For information on UK legislation relating to birth statistics and for definitions of terms please see the Births metadata and the tables for the appropriate births package.

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9. Other information

Output quality trade-offs

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

The Migration Indicator Tool enables comparison of data published by Office for National Statistics (ONS), National Records of Scotland (NRS), Northern Ireland Statistics and Research Agency (NISRA), Department for Work and Pensions (DWP), Home Office (HO) and Patient Register Data Service (PRDS) to gain an indication of migration at local level.

The different data sources that are used to compile the Local Area Migration Indicators Suite have various levels of accuracy and timeliness.

As mentioned previously, the indicators used in the suite are from various data sources, which use different definitions and count different types of migration. Care needs to be taken when comparing the data, although the data can be used to compare different indicators as well as different geographical areas.

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10. Assessment of user needs and perceptions

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

The most recent consultation on international migration statistical outputs took place between 11 November 2016 and 23 December 2016. In summary, this consultation showed that users would like:

  • data at lower geographical levels
  • the ability to manipulate data to a greater extent
  • the option to use a data explorer tool to run their own cross-tabulations
  • the option to compare different sources of data

We consult users on our statistical work programme every 4 years via our website. The most recent consultation was held between 1 November 2010 and 24 December 2010 and responses were used to inform our work programme between 2011 to 2012 and 2014 to 2015. Stakeholders were asked to provide information on which of our outputs they use, how they use them and their views on the impact for them of possible reductions in various areas of our work following the 2010 Spending Review. The consultation confirmed there is widespread user support for population statistics such as the Long-Term-International Migration and International Passenger Survey (IPS) estimates.

The Migration Statistics Improvement Programme (MSIP) was a substantial programme that included taking forward the recommendations of the 2006 Interdepartmental Task Force on Migration Statistics and the more recent Treasury Select Committee report Counting the Population. Phase 1 of MSIP ended in May 2010 and resulted in significant improvements to migration and population statistics including:

  • revised population estimates at local authority level for 2002 to 2008 based on improved model-based immigration estimates; the improvements included the use of more timely administrative data and an adjustment for student moves, pre- and post-university, based on new data
  • changes to the IPS sample to optimise it for migration, for example, by introducing new sites to reflect the changing flows of migration
  • published estimates of short-term migrants and publication of the Local Area Migration Indicators Suite
  • improved access to administrative data relevant to estimating migration including data from the Higher Education Statistics Agency
  • improved reporting through the production of Migration Statistics Quarterly Reports, which include migration data from other government departments

Phase 2 of the MSIP ran until March 2012. It consisted of three key work streams:

  • reconciling administrative sources and population estimates
  • improving migrant distribution
  • statistical benefits of e-borders

The MSIP team held a series of end of programme seminars to present research and findings to stakeholders and statistical users, to make sure they were fully engaged with the programme achievements. This series of seminars aimed to review the success of the programme and outlined plans for taking forward future improvements. The objectives of these seminars were:

  • updates for stakeholders, presentations included:

  • reflecting on the success of the programme

  • short-term migration
  • measures of uncertainty
  • reconciling administrative sources
  • looking ahead to future plans for improving population statistics
  • an opportunity for attendees to discuss the achievements of the programme
  • to gather feedback from stakeholders on the developments from Phase 2 of the MSIP
  • to meet the requirement of the Code of Practice for Official Statistics to “engage effectively with users of statistics to promote trust and maximise public value”

The Home Office launched a consultation concerning immigration statistics from 24 February 2011 to 4 May 2011. Also, the UK Statistics Authority has reported on Migration Statistics - The Way Ahead and the recommendations can be found in their report.

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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:

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