The current methodology for determining assumptions of future migration was introduced for the 1991-based national population projections.1 With some later modifications,2 this approach, which standardises the methods and procedures by which the assumptions are formulated, has been the basis of subsequent projections. This chapter summarises the assumptions adopted for the 2010-based population projections.
It is important to emphasise that the migration assumptions are based on past demographic trends. They do not attempt to predict the impact that new or future government policies, changing economic circumstances or other factors (whether in the UK or overseas) might have on migration patterns.
The new long-term assumption for net migration to the UK is +200,000 each year compared with +180,000 a year in the 2008-based projections. Figure 5.1 compares the future net migration assumptions with historical international migration estimates back to 19913 and also includes the assumptions made for the previous 2008-based projections. It is based on mid-year to mid-year, rather than calendar year figures, so the latest ‘actual’ data point shown is the estimated total net inflow to the UK of 227,000 between mid-2009 and mid-2010.
ONS uses the United Nations recommendation for defining an international long-term migrant. That is, someone who changes their country of usual residence for a period of at least a year, so that the country of destination effectively becomes the country of usual residence.
Migration figures are derived from several sources.4 The principal source is the International Passenger Survey (IPS) which became operational in 1964. The IPS provides estimates based on respondents’ intended length of stay in the UK or abroad. Therefore, some statistical adjustments are made for people who change their intentions – ‘visitor switchers’ and ‘migrant switchers’.
Visitor switchers are people who enter or leave the UK for a short visit (that is, less than 12 months) but end up migrating for more than a year. These people are visitors who subsequently become migrants and therefore need to be added to the migration estimates.
Migrant switchers are people who state in the IPS that their intention is to remain in their destination country for more than a year (and are therefore classed as migrants) but who actually leave, or return to, the UK within one year, so are actually visitors. They need to be removed from IPS migrant flows. This is effectively the converse situation to visitor switchers.
The IPS excludes most, but not all, persons seeking asylum and some dependants of such asylum seekers. Therefore, an adjustment for those not covered by the IPS is necessary. Data on asylum seekers and their dependants (based on the number of people applying for asylum) obtained from the Home Office, are used to estimate the number of migrants arriving or leaving the UK.
Since the last projections round, the Migration Statistics Unit (MSU) at ONS has made two adjustments in the methodology to produce long-term international migration estimates.5 They relate to Northern Ireland and the Republic of Ireland:
From 2008, the ONS migration estimates no longer use IPS data for Northern Ireland and instead use data from the Northern Ireland Statistics and Research Agency (NISRA). Therefore, in making the long-term assumptions, IPS international UK gross flows are allocated to all the constituent countries but the allocations to Northern Ireland are not used. Any difference between the allocations to Northern Ireland and the NISRA derived assumptions are added to England in the form of a consistency adjustment so as to maintain the original UK IPS totals. In addition - since NISRA incorporates visitor and migrant switchers, asylum seekers and Republic of Ireland flows in their data - the adjustments/ assumptions for these components are at Great Britain (GB) level for the 2010-based projections.
Republic of Ireland
Estimates of flows between the UK and the Republic of Ireland are based on the Irish Quarterly National Household Survey and the National Health Service Central Register (NHSCR) and are agreed between the Irish Central Statistics Office (CSO) and ONS. The IPS figures (for data from 2008) now incorporate the ROI, but there is a discontinuity between 2008 and earlier years as revisions to back series have not been run. Therefore, it was decided to exclude ROI flows from the IPS data and continue to base long-term assumptions of migration between the ROI and GB on CSO data until there is a longer time series.
Migration covered by the International Passenger Survey (IPS)
The IPS time-series was projected forward using a form of exponential smoothing but with the various trends gradually 'levelled off' to give constant level projections after ten years. However, to avoid giving the impression that small year to year future changes can be accurately predicted, the average net flow projected for the next ten years is taken as the basis for the long-term assumption as shown by the blue horizontal lines in Figure 5.2. The model projection is based on final data up to 2009. Final data for 2010 did not become available until after the National Populations Projections were published, but provisional 2010 data was used in formulating the short-term assumptions.
The assumed long-term annual IPS net inflow given by the model is 175,000 (an inflow of 530,000 and outflow of 355,000). The corresponding figure from the 2008-based projections (based on final data up to 2007 and provisional data for 2008) was 155,000 (an inflow of 515,000 and an outflow of 360,000). The effect of adding (final) IPS data for 2008 and 2009 has therefore been to increase net inflows by 20,000.
The same projection method has also been applied to flows between the UK and four different groups of countries: (a) the Old Commonwealth6 & USA; (b) the New Commonwealth; (c) the European Union (excluding the A8 and A2 accession countries)7 and (d) the Rest of the World. All the flows are considered separately for British and non-British citizens. These projections are shown in Figures 5.3 to 5.10.
The country breakdown is complicated by the enlargement of the EU in May 2004 and January 2007.8 To avoid the possibility that migration from the A8 and A2 accession countries might distort underlying trends, A8 and A2 migration flows were excluded from the IPS modelling. Instead, a separate allowance has been made for additional net migration from the A8 and A2 accession countries up to and including 2015–16, with net flows assumed to be zero in the long-term (from 2016–17).
The projection method used is additive that is, the same results are produced by applying the method to each of the eight categories and summing the results as are obtained by applying the method directly to the total migration flows. The advantage of applying the method to these separate, relatively homogeneous categories is that it may shed light on the key factors underlying the overall trends.
However, when disaggregated in this way, IPS sample numbers can become quite small. Therefore, although the projections of the eight categories (shown in Figures 5.3 to 5 .10) can be considered separately, they are not as robust as those for the total migration flows (in Figure 5.2) and thus the breakdown of the overall IPS assumptions shown in Table 5.1 should be regarded as purely illustrative. Nevertheless, it is clear that the overall projected IPS net inflow is a result of large inflows from all the categories of non-British citizens, partially offset by outflows of British citizens to the Old Commonwealth & USA and to the European Union (excluding A8 and A2 countries) in particular.
|Illustrative breakdown of IPS component|
|Old Commonwealth & USA||25||80||-55|
|European Union (excluding A8 & A2)||25||60||-40|
|Rest of the World||15||30||-15|
|Old Commonwealth & USA||80||60||20|
|European Union (excluding A8 & A2)||75||50||25|
|Rest of the World||135||40||95|
|Total IPS migration||530||355||175|
IPS data excludes estimates of migration flows to/from the A8 and A2 accession countries and also to/from the Republic of Ireland (applicable from 2008). A separate allowance is made for migration to/from these countries.
Visitor switchers and migrant switchers
The adjustments made for projections are consistent with those made by ONS in recent international migration estimates. However, as with the IPS modelling above, estimates of A8 and A2 visitor switcher flows have been removed from the series as accession flows are considered separately.
Due to a change of methodology that was implemented in 2007 for estimating visitor switchers from 2004 onwards, and the fact that NISRA data already incorporates visitor switchers to/ from Northern Ireland; an average of GB data from 2004 to 2009 was taken, resulting in an annual net visitor switcher adjustment of +15,000, (an inflow of 30,000 and an outflow of 15,000). This compares with an annual UK net visitor switcher adjustment of +20,000 (an inflow of 35,000 and an outflow of 15,000) from the 2008-based projections.
A corresponding allowance to that made for visitor switchers needs to be made for migrant switchers. Similarly to visitor switchers, a change of methodology was implemented in 2007 for estimating migrant switchers from 2004 onwards. Again, an average of GB data (excluding A8 and A2 countries) from 2004 to 2009 was taken resulting in an annual net migrant switcher adjustment of -5,000 (an inflow of -20,000 and an outflow of -15,000). This compares with an annual UK net migrant switcher adjustment of zero (an inflow of -15,000 and an outflow of -15,000) from the 2008-based projections.
Republic of Ireland
Over the last decade, GB has consistently lost population to the ROI but this pattern has reversed in recent years. Taking a five-year average of GB data (2006–2010) and following consultation with the Irish Central Statistics Office (CSO), an assumption of an annual zero net flow from ROI to GB was made (an inflow of 10,000 and an outflow of 10,000). This compares with an annual UK net outflow to the ROI of 5,000 (an inflow of 10,000 and an outflow of 15,000) from the 2008-based projections.
The asylum seeker adjustment has been formulated by ONS in consultation with the Home Office. The latest data show fairly constant level inflows from 2004 and a gradual reduction in outflows over the same period. Therefore, an average of GB data from 2004 to 2009 was taken resulting in an annual net asylum seeker adjustment of +15,000 (an inflow of 25,000 and an outflow of 10,000). This compares with an annual UK net asylum seeker adjustment of +10,000 (an inflow of 25,000 and an outflow of 15,000) from the 2008-based projections.
Therefore, - summing together the IPS and ROI long-term assumptions along with visitor switcher, migrant switcher and asylum seeker adjustments - annual net migration to the UK is assumed to be 200,000 in the long-term, as illustrated by Table 5.2.
|Visitor switcher adjustment||15,000||20,000||-5,000|
|Migrant switcher adjustment||-5,000||0||-5,000|
|Asylum seeker adjustment||15,000||10,000||5,000|
Gross migration flows
Gross migration flows (that is, inflows and outflows) are not required in order to produce the projections. The methodology used, therefore, focuses on net flows. Table 5.3 does show nominal gross flows for the various components (IPS, asylum seekers etc) although these exclude migration flows to/ from the accession countries which are considered separately. However, these gross flows should be treated with caution. For example, for the IPS component, the average net flow over the next ten years (obtained from the projection model) is used as the basis for the (constant) long-term assumption. While it may be defensible to assume constant net flows (and this is common practice amongst national projection makers worldwide), it is less realistic to assume that gross flows will remain constant.
|Total IPS migration||530||355||175|
|Adjustment to IPS data|
|Total civilian migration||575||375||200|
Allocation of international migration to the constituent countries of the UK
International migration estimates for the constituent countries of the UK were revised in 2007 following the introduction of a new methodology9 that adjusts the IPS data to the geographical distribution of international inflows provided by the Labour Force Survey. The reasons for this change in methodology (known as “calibration”) was that migrants identified by the IPS are thought to be more likely to state London as a destination in preference to other lesser known places, and also some in-migrants may quickly move from an initial destination point in London to another region of the country. This improved methodology was implemented back to 1999.
The allocations of IPS international UK inflows/ outflows to England, Wales, Scotland and Northern Ireland are based on a ten-year average of IPS estimates for the years 2000 to 2009 under the calibration methodology. As stated previously, data for Northern Ireland are provided by NISRA, so any difference between the allocation of IPS data to Northern Ireland (which are not used) and the NISRA derived assumptions, are added to England in the form of a consistency adjustment so as to maintain the original UK IPS totals.
The long-term assumption for Northern Ireland was derived by taking a five-year average (2006–2010) of the total gross flows estimated by NISRA. The result is an assumption of zero annual net migration (an inflow of 7,500 and an outflow of 7,500). As with the long-term assumptions for the rest of the UK, recent A8 flows were deducted from the Northern Ireland data and an allowance for additional short-term net-migration from A8 countries was added separately.
Since NISRA already incorporates the other component categories - visitor and migrant switchers, asylum seekers and ROI flows - in their data; the allocation of inflows and outflows to England, Wales and Scotland are based on GB level data for these components.
As a result, the assumed annual long-term net inflows through international migration are 188,000 to England, 3,000 to Wales, 9,000 to Scotland and zero to Northern Ireland. Table 5.4 shows that the assumption for Northern Ireland is lower compared to the 2008-based projections; the assumptions for England and Scotland are higher and the assumption for Wales remains unchanged.
Regular estimates of the movements of population between the countries of the UK are made by ONS, NRS and NISRA. These estimates are based on changes of residence recorded by the National Health Service Central Register (NHSCR). At the time of setting the assumptions for the 2010-based projections, two additional years of NHSCR data (for 2008–09 and 2009–10) have become available since the 2008-based projections were prepared.
The long-term assumptions for migration between England and the other constituent countries are:
• Between England and Wales. Wales has experienced a net gain in population from England throughout the last ten years. The net flows have fallen from a peak of over +14,000 in 2002–03 to less that +2,000 in each of the last two years. In consultation with the Welsh Government, it was agreed to assume a long-term annual net flow from England to Wales of 7,000 persons per year, (based on the average net gain over the last ten years). This compares with an assumption of 7,500 in the previous projections round.
• Between England and Scotland. Net flows from England to Scotland remained at high levels between 2003–04 and 2007–08 but have fallen in the last two years. In consultation with NRS, it was agreed to assume a long-term annual net flow from England to Scotland of 8,500 a year (based on the average net gain over the last ten years). This compares with an assumption of 6,500 in the previous projections round, although that incorporated positive net flows from Scotland to England for the years 1998–99 and 1999–2000.
• Between England and Northern Ireland. Flows between England and Northern Ireland have fluctuated around a net balance of moves. In consultation with NISRA it was agreed to retain the 2008-based assumption of zero net migration between the two countries.
For the flows between the three smaller countries, the ten year averages remained around net zero for both Wales to Scotland and Wales to Northern Ireland, unchanged from the 2008-based assumptions. It was also agreed (between ONS, NRS and NISRA) to keep the assumption of zero net flows between Scotland and Northern Ireland.
The assumed annual long-term cross border net inflows are therefore, -15,500 to England, +7,000 to Wales, +8,500 to Scotland and zero to Northern Ireland. These assumptions are compared with those from the 2008-based projections in Table 5.4.
Numerically, the dominant flows within the UK are between the smaller countries and England. Figures 5.11-5.13 show the trend in these flows between 1998–99 and 2009–10. Moves from England are plotted against the vertical axes and moves to England are plotted on the horizontal axes. Therefore, points above the dashed diagonal line indicate a net outflow from England, while points below the line indicate a net inflow into England; the greater the distance the points are from the dashed line, the greater is the net migration flow. Note that the scales differ in the three charts. In particular, flows to and from Northern Ireland are much smaller than those to and from Wales and Scotland.
Combining the assumptions of international net migration (where long-term net flows from accession countries are assumed to be zero) and cross border flows, gives total net migration of 172,500 to England, 10,000 to Wales, 17,500 to Scotland and zero to Northern Ireland. Table 5.4 shows that the assumptions for Wales and Northern Ireland are lower compared to the 2008-based projections and the assumptions for England and Scotland are higher.
|International net migration|
|Cross-border net migration|
|Total net migration|
The projections assume constant levels of annual net migration beyond 2016–17. In reality, of course, migration will inevitably continue to fluctuate from year to year, but such long-term fluctuations are impossible to predict. The assumptions should therefore be regarded as representing average annual levels of net migration for the future.
Special assumptions have been applied for the first few years of the projections (2010–11 to 2015–16) and are summarised in Table 5.5. These short-term assumptions were decided after the long-term assumptions, in order to take account of the most up to date data available. They differ from the long-term assumptions for the following four reasons:
(a) The assumptions for 2010–11 take account of provisional estimates of long term international migration (LTIM) for 2010 (calendar year) and additional provisional cross border migration data, from the NHSCR, for the second half of 2010. Data from NISRA are largely based on changes in health card registration between July 2010 and June 2011.
(b) Net migration from the countries which joined the EU in May 2004 is estimated to have fallen to 21,000 in 2008–09 but, according to the latest (provisional) estimates, has risen to 46,000 in 2010–11 (see Figure 2.2 of the Migration Statistics Quarterly Report February 2012).10 An allowance has been made for additional net migration which totals +120,000 over the five years from 2011–12 to 2015–16 from the accession countries which joined the European Union in May 2004 and January 2007. The assumption is that net migration will decline from +40,000 in 2011–12 to net zero in the long term. Note: The accession country component was not separately identified for the first year of the projection (2010–11).
(c) For cross border migration, the figures for the first three years of the projection (2010–11 to 2012–13) assume a gradual transition from current migration levels to the assumed long-term levels. For international migration (non-accession) and at constituent country level only, the figures for the years 2011–12 to 2013–14 also assume a gradual transition to assumed long-term levels.
(d) An allowance has been made for the return of 2,000 Armed Forces (including dependants) from Germany to the UK during the period 2012–13 to 2015–16. They have all been assumed to return to England.
|United Kingdom||England||Wales||Scotland||Northern Ireland|
|Total net migration|
|2016-17 onwards - long-term assumption||200.0||172.5||10.0||17.5||0.0|
|International migration assumption for 2010-111|
|International migration assumption (non-accession)|
|2016-17 onwards - long-term assumption||200.0||188.0||3.0||9.0||0.0|
|Allowance for additional net migration from accession countries2|
|Returning Armed Forces from Germany (including dependants)|
|2012-13 to 2015-16 (annual)||0.5||0.5||0.0||0.0||0.0|
Long-term impact of enlargement of the European Union
No allowance has been made for additional net migration from these countries beyond 2015–16. However, clearly there is great uncertainty about this. With other EU countries gradually opening their labour markets to accession country citizens - due to the end of the transitional arrangements for the A8 countries from May 2011 and the A2 countries from January 2014 - and the likelihood of the economies of the new countries gradually ‘catching up’, most experts believe that net migration from these countries will reduce.
In line with ONS estimates of total international migration, no explicit or separate allowance has been made in the projections for illegal migrants entering the UK.
Points-based system for immigration and student fees
In February 2008, a new points-based system 11 for controlling non-EU immigration to the UK was introduced. The long-term assumptions for the 2010-based projections were based on past trends and, as noted in the introduction to this chapter, no attempt was made to predict the future impact of this or other new government policies, on migration behaviour.
Similarly, variations in policy on student fees between the countries of the UK is not considered when setting the trend based cross-border migration assumptions.
Age and sex distribution
For England, Wales and Scotland, the assumed age and sex distribution of international migrants has been based on ONS estimates of the age/sex distributions of the various component categories – IPS, visitor switchers, migrant switchers, asylum seekers and ROI. The assumed distributions are based on averages of the last five years’ data (2005-2009).
For Northern Ireland, where the long-term total migration assumption was not broken down into component categories, age and sex distributions were applied based on IPS data for the UK. For migration to/ from accession countries, age and sex distributions were also based on IPS data for the UK. For cross-border migration, separate age and sex distributions, based on NHSCR data, were calculated for each constituent country.
In each case the age and sex distributions were considered separately for immigrants and emigrants. The long-term net migration distribution for the UK is summarised in Table 5.6. The table shows that the projections assume slightly more male migrants than female migrants. Equivalent tables for the constituent countries and further tables containing in- and out-migration by age and sex are available on the ONS website.12
|0 - 4||4.3||2.1||2.2|
|5 - 9||2.2||0.9||1.4|
|10 - 14||3.5||1.4||2.1|
|15 - 19||39.9||19.4||20.4|
|20 - 24||89.0||44.6||44.4|
|25 - 29||45.9||28.0||17.9|
|30 - 34||15.0||7.9||7.1|
|35 - 39||7.7||4.2||3.5|
|40 - 44||0.0||-1.5||1.5|
|45 - 49||1.9||-0.1||2.0|
|50 - 54||0.9||1.1||-0.3|
|55 - 59||-2.8||-2.3||-0.5|
|60 - 64||-4.6||-2.5||-2.1|
|65 - 69||-2.9||-0.9||-2.0|
|70 - 74||-0.4||-0.5||0.1|
|75 & over||0.5||0.1||0.4|
The assumed age distributions for international migration to and from the UK, and the NHSCR derived distributions for cross-border migration for England, are shown in Figures 5.14-5. 17. All these distributions are highly peaked at the young working ages, which was also the case for the distributions assumed for cross-border migration for Wales, Scotland and Northern Ireland.
Consideration of how migration assumptions are prepared in other countries and by other agencies13 ,14 suggests that, as in the UK, migration assumptions tend to be based largely or solely on past demographic trends. While many projection makers say that their assumptions are also informed by expert opinion, few use immigration assumptions “that are justified by any explicit reference to a theory of how or why immigration happens”.13 It is therefore perhaps helpful to summarise some of the current arguments put forward by experts regarding future levels of net migration in the UK.
The NPP Expert Advisory Panel (ten academic demographic experts convened by the British Society for Population Studies) met in March 2011.15 In an accompanying questionnaire,16 the experts were asked for their opinions on the likely levels of international migration to and from the UK in 2014 and 2034 (that is, five years and twenty-five years into the future from – at the time - the latest (2009) estimates). Note: the experts were not asked to exclude A8 and A2 accession countries.
The NPP Expert Advisory Panel – views on migration in the long-term
The average annual net migration derived from the experts’ responses for 2034 was a net inflow of +162,000 per year (with an average 67 per cent confidence interval of 108,000 to 227,000). This is much lower than the proposed 2010-based long-term assumption for net migration to the UK of +200,000 per year.
The experts were also asked to consider five overall forces with the potential to affect levels of net migration to the UK in the long-term and assess the importance and likely impact of each force upon future migration.
On average, three forces were considered to be equally important in determining future migration, namely, “trends in the main motives for migration”, “trends in migration pressure resulting from changes in the countries of origin” and “trends in the attractiveness of the UK as a country of destination”. The majority of experts considered the first two forces to have at least a small upwards influence on total net migration, but there was little consensus on the third force. Whereas the majority of experts thought the force “Effectiveness of controls on migration flows” would have a small downwards influence on total net migration, although this force was rated second least important of the five forces. The force “Costs of migration (in the broader sense)” was rated the least important.
Eight of the experts thought the current global economic climate would not have a significant impact on migration flows to and from the UK beyond 2014. However, seven of these thought any impact it did have would last beyond two years.
The NPP Expert Advisory Panel – views on migration in the short-term
The annual net migration derived from the experts’ responses for 2014 was a net inflow of +171,000 per year (with an average 67 per cent confidence interval of 134,000 to 215,000). This is somewhat higher than the corresponding experts’ average for 2034 (+162,000 per year) but much lower than the proposed 2010-based long-term assumption of +200,000.
It should be noted, however, that trends in underlying ‘push’ and ‘pull’ factors in western countries do not automatically follow through to corresponding trends in net migration. For example, increases in the numbers of people wishing to enter a country may lead governments to consider more targeted or restrictive immigration policies. The different responses of EU governments to the opening of their labour markets to people from the new accession countries is a reminder that migrant numbers are not just dependent on the demographic characteristics of the sending and receiving countries, but will also be affected by any intervening obstacles or incentives placed on their movement. And the UK government has itself recently introduced a new points based system for controlling non-EU immigration to the UK.11
The experts were asked if they thought the points-based system would have an impact on the level of in-migration to the UK from non-EU/European Economic Area (EEA) countries in 2014. The majority (six) thought it would have an impact with five experts suggesting there would be a small downward influence.
There is evidence that levels of international migration are correlated with economic factors such as unemployment rates, although the strength of the relationship may vary from country to country.17 Nevertheless, few agencies explicitly use explanatory variables (whether economic or other), in projection making, other than perhaps in the very short-term. This is often because the explanatory variables are considered to be as, or more, difficult to predict than the demographic variables. If a prolonged change in the relative strength of the UK economy occurs, the UK may face increasing competition for migrants both from other EU countries and also from economically emerging nations outside the EU.
Latest Eurostat and UN projections
In their latest ‘EUROPOP2010’ projections published in May 2011,18 Eurostat assumed a convergence scenario whereby net migration to all EU countries would converge to zero at a point in the future beyond the scope of the projections. Eurostat therefore assumed a gradual decline in net in-migration to the UK from 198,000 per year in 2010 to 178,000 per year in 2030 and 134,000 per year in 2060. These assumptions are all higher than in the previous ‘EUROPOP2008’ projections where they assumed a gradual decline in net in-migration to the UK from 188,000 per year in 2008 to 151,000 per year in 2030 and 114,000 per year in 2060.
The latest official United Nations population projections (2010 Revision) published in May 201119 assume a level of net migration to the UK of 209,000 a year from 2010 to 2015. They assume varying levels of migration for each five years which averages at 195,000 from 2015 to 2030 and then declining migration to 22,000 by 2055–2060.
1. National population projections: a new methodology for determining migration assumptions. Occasional Paper 42. OPCS (1993)
2. National population projections: 1996-based, ONS Series PP2 no 21. The Stationery Office (1999). Footnote to p34.
3. For further information see Long Term International Migration 2 series (LTIM) 2010 available at: www.ons.gov.uk/ons/publications/re-reference-tables.html?edition=tcm%3A77-235198
4. For further information see Long-term international migration estimates methodology available at: www.ons.gov.uk/ons/guide-method/method-quality/specific/population-and-migration/international-migration-methodology/index.html
5. For further information see Long-term international migration - Irish methodological changes available at: www.ons.gov.uk/ons/rel/migration1/long-term-international-migration/2008/irish-methodological-changes.pdf
6. The Old Commonwealth is defined as Australia, Canada, New Zealand and South Africa. The New Commonwealth is defined as Other African Commonwealth countries, Indian subcontinent and other Commonwealth countries in the Asian, Caribbean and Oceania regions. For further information see Background notes and guidelines for long-term international migration estimates available at: www.ons.gov.uk/ons/guide-method/method-quality/specific/population-and-migration/international-migration-methodology/background-notes-and-guidelines-for-long-term-international-migration-estimates.pdf
7. The European Union was taken to be the 15 member states of the EU as constituted before 1 May 2004 (excluding the Irish Republic which is considered separately), plus Cyprus and Malta.
8. Ten countries joined the EU in May 2004: the A8 accession countries from Eastern Europe (the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovenia and Slovakia) plus Cyprus and Malta. And the A2 accession countries, Bulgaria and Romania, joined in January 2007.
9. For further information see The Use of Calibration in Estimating International In-Migration available at: www.ons.gov.uk/ons/guide-method/method-quality/imps/archive-material/archive-background-information/improved-methods-for-population-statistics-revisions--archive-material-/the-use-of-calibration-in-estimating-international.pdf
10. For further information see Migration Statistics Quarterly Report February 2012 available at: www.ons.gov.uk/ons/rel/migration1/migration-statistics-quarterly-report/february-2012/msqr.html#tab-2--Who-is-Migrating-to-and-from-the-UK--Migration-by-Citizenship
11. For further information see Points-based System available at: www.ukba.homeoffice.gov.uk/policyandlaw/immigrationlaw/immigrationrules/part6a/
12. Tables can be downloaded from 5. Migration assumptions: 2010-based national population projections, available at: www.ons.gov.uk/ons/rel/npp/national-population-projections/2010-based-projections/rep-2010-based-npp-migration-assumptions.html#tab-Age-and-sex-distribution
13. Howe N and Jackson R. Projecting immigration: A Survey of the Current State of Practice and Theory. Centre for Strategic & International Studies, Washington DC (2005). Available at: csis.org/files/media/csis/pubs/0504_howe_jacksonprojimmigration.pdf
14. Questionnaire on Population Projections: Report on the latest national practices. Paper for Eurostat Working Group on Population Projections. Eurostat (2006).
15. NPP Expert Advisory Panel minutes of meeting held on March 2011 available at: www.ons.gov.uk/ons/rel/npp/national-population-projections/2010-based-projections/rep-2010-based-npp.html#tab-Appendix-A--Note-of-the-meeting-of-the-national-population-projections-expert-advisory-group
16. NPP Expert Advisory Panel questionnaire results available at: www.ons.gov.uk/ons/rel/npp/national-population-projections/2010-based-extra-variants/rep-2010-based-npp-extra-variants.html#tab-Appendix-C--Charts---National-population-projections-expert-advisory-panel-
17. Analysis and forecasting of international migration by major groups. Eurostat Working Paper 3/2002/E/no. 17. Eurostat, 2003 available at : epp.eurostat.ec.europa.eu/portal/page/portal/product_details/publication?p_product_code=KS-AP-01-032
18. Europop2010 projections available at: epp.eurostat.ec.europa.eu/statistics_explained/index.php/Population_projections
19. UN population projections (2010 revision) available at: esa.un.org/unpd/wpp/
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