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Short-Term Migration in the UK: A Discussion of the Issues and Existing Data

13 Oct 2017

This briefing sets out to explain the often confusing issue of how we define a short-term migrant and looks at the estimated numbers of short-term migrants in the UK, how long they are staying, why they come to the UK and where they come from.

  1. Key Points
    • The ONS publishes short-term migration estimates for England and Wales, using two definitions of a short-term migrant (migrants staying less than 12 months): those staying for a minimum of one month and those staying for at least three months. More…
    • The 1 to 12 months definition suggests a short-term migration in-flow (the number of short-term migrants travelling into England and Wales over a given period of time) of 1.2 million people in the year to June 2015, while the 3 to 12 months definition puts the number at 304,000. More…
    • Employment and study reasons accounted for just over half of 3-12 month short-term migration to England and Wales. In the year to June 2015, 69,000 people came for short-term study reasons, down from 87,000 the year before, and 91,000 came for employment reasons, up from 79,000 in YE June 2014.More…
    • The estimates suggest that about 247,000 short-term migrants were residing in England and Wales in the year to mid-2015 for the 1 to 12 months definition and about 128,000 for the 3 to 12 months definition.More…
    • The outflow of short-term migrants (3 to 12 months definition) in the year to mid-2015 was 390,000 and the estimated number of UK residents living for a short-period in another country was 156,000.More…
    • In 2015, Poland was the most common country of previous residence of short-term migrants staying 1-12 months (inflow of 89,000 in the year to mid-2015), while Romania was the most common country of previous residence for migrants staying 3 to 12 months (inflow of 31,000 in the year to mid-2015). More…
    • Newham was the top local authority in terms of the number of 3-12 month short-term migrants for study or work in YE mid-2015, followed by Manchester and Birmingham. More…
  1. Understanding the Evidence

    Most of the UK’s migration statistics provided by the UK Office for National Statistics (ONS), including those on immigration, emigration and net-migration, refer to ‘long-term migrants’ defined as people migrating to the UK for at least 12 months. These data do not include people moving to or leaving the UK for less than 12 months.

    However, the ONS also reports data on short-term migrants defined as someone staying in the UK for less than a year, and either at least one month or at least three months. In May 2016, the ONS published a note analysing the difference between the commonly reported long-term immigration figures and the number of people registering for National Insurance Numbers (NiNos), following public debates about why NiNo registrations were significantly higher than estimated long-term immigration (ONS 2016). The note argues that short-term migration is likely to be largely responsible for the gap.

    The data used in this briefing come from the ONS Mid-Year Short-Term Migration Estimates for England and Wales. These refer to ‘year to mid’ estimates – for instance, the figures for 2015 reflect estimates for the year from mid-2014 to mid-2015 (year ending June). These estimates were published for the first time as fully accredited National Statistics in February 2011 and are constructed mainly with data from the International Passenger Survey (IPS).

    The ONS publishes short-term migration figures for England and Wales, using two definitions of a short-term migrant: those staying for a minimum of one month or three months. These definitions are broader than the United Nations definition of short-term migration: moves made for between 3 and 12 months for employment or study.

    Short-term migration figures are complicated by a number of factors in the measurement of short-term migrant numbers – not least, the understanding that many holidaymakers and business travellers are covered in the data.

    The ONS provides estimates of short-term inflows of migrants (and outflows of UK residents) and populations of short-term migrants in the UK and abroad (also known as the ‘in-stock’ and ‘out-stock’, respectively). The term inflow refers to the number of short-term migration visits from individuals that typically reside outside the UK (i.e. these individuals have to reside outside the UK for at least 12 months). The ‘in-stock’ denotes the stock of short-term migrants present in the UK during a specified period (number based on person years). The out-stock refers to the number of UK residents living for a short-period in another country. See the Evidence gaps and limitations section for further details. For simplicity, this briefing also refers to the in-stock and out-stock as ‘populations’ of short-term residents.

Using a 3-12 months stay to define a “short-term migrant” puts the number coming to England and Wales at 304,000 in the year to mid-2015

Figure 1 shows the number of in-flows of short-term migrants to England and Wales between the year ending in mid-2004 to the year ending in mid-2015 using the two definitions of short-term migrants; planning to stay (a) 1 to 12 months, and (b) 3-12 months.

Short-term migration in-flows to England and Wales had been on a downward trend since mid-2006. However, the latest available data suggest a small increase, using both definitions. Figure 1 also suggests that there is a significant difference between the two definitions and estimates. While the 1 to 12 months definition suggests a short-term migration in-flow of 1.2 million in 2015, the 3 to 12 months definition puts the number at 304,000.

Figure 1

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Employment and study reasons in England and Wales account for just over half of 3-12 months stays

Table 1 reports short-term migrants’ reasons for coming to England and Wales based on data for 2015, using the 3 to 12 months definition. This enables us to identify short-term migrants under the United Nations definition, which excludes people moving for reasons other than work or study.

Latest data suggest that about 23% of 3-12 month short-term migrants come for study purposes; many are likely to come for short-term English courses. Around 30% come for employment in England and Wales. Those who come for employment may include non-EU nationals in different visa categories (including Intra-Company Transfers) and EU nationals who have free access to the UK labour market. The remaining 47%–who would not be short-term migrants by the UN definition—come for other reasons, including leisure, visiting friends or family, and doing business.

Table 1 – Reasons for short-term visits year ending mid-2015

ReasonShare
Employment30%
Study23%
Other47%

Source: Office for National Statistics, Mid-2015 Short-term Migration Estimates for England and Wales. Note: Based on the 3-12 months definition. The reference period is year to mid.

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The population of short-term migrants resident in England and Wales increased in the year to mid-2015

As shown in Figure 2, between 2004 and 2006 the number of short-term migrants residing in England and Wales (known as the ‘in-stock’) was on an upward trend, reaching a peak of 290,000 (1-12 months stayers) or 149,000 (3-12 months stayers) in mid-2006. This was followed by consecutive decreases between 2007 and 2010. The population of short-term migrants in England and Wales increased from 2013 to 2015, reaching 247,000 (1-12 months stayers) or 128,000 (3-12 months stayers) in YE mid-2015.

Figure 2

Table 2 shows the mean length of stay in months among the resident population of short-term migrants by reason for migrating and using the two duration definitions. Among those staying for 3-12 months, the mean length of stay is 5.3 months. As could be expected the average stay is shorter using the 1 to 12 months definition. In 2015, it stood at 2.5 months on average. For short-term migrants coming for 3-12 months, the different reasons for migrating have similar intended lengths of stay, from 5.7 months (employment) to 5.0 (other). However, in the 1-12 months definition, those coming for employment reasons report a longer intended stay of 4.0 months, compared to those who migrate for other reasons at 2.3 months.

Table 2 – Mean length of stay for the in-stock by reason for visit for the different definitions (in months) for 2015

DefinitionEmploymentStudyOtherAll
3 – 12 months5.75.55.05.3
1 – 12 months4.03.12.32.5
Difference1.72.42.82.8

Table 3 shows the shares of inflows and population of short-term migrants who come for employment, study, or other reasons, using the two duration definitions. For the 1-12 months definition, 14% of inflows and 20% of the resident short-term population reported coming for employment according to latest figures. In the 3-12 months definition, 30% of both inflows and population stated employment related reasons.

Between 2006 and 2012, employment related stays saw annual decreases (from 29% in 2006 to 21% in 2012, 3-12 months), while study related reasons became more important (from 22% in 2006 to 30% in 2012, 3-12 months). For the years ending in mid-2014 and mid-2015, employment reasons were on a small upward trend.

Table 3 – Shares of in-flow and in-stock by reason for different definitions

 EmploymentStudyOther
In-flows (1-12 months)14%17%69%
Short-term resident (1-12 months)20%20%60%
In-flows (3-12 months)30%23%47%
Short-term resident (3-12 months)30%24%47%

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The out-flow and out-stock of short-term migrants is usually higher than the in-flow and in-stock

The out-flow and out-stock of short-term migrants refer to individuals who are usually resident in England and Wales but who are on short-term stays abroad. The short-term migration out-flow and out-stock usually exceeds the short-term in-flow and in-stock. That is, there are more UK residents temporarily staying abroad than non-UK residents temporarily staying in the UK. However, it is not as straightforward to talk about net figures for short-term migration as it is for long-term migration, given that these estimates refer to short-term moves within a year.

Figure 3 reports the out-flow and out-stock series for the 3 to 12 months definition. The out-flows and out-stock of short-term migrants in the year ending in mid-2015 stood at 390,000 and 156,000 respectively.

Figure 3

The mean length of stay abroad for people living temporarily abroad (3-12 month out-stock) was 5.0 months in 2015. Those who spent time abroad for work reasons stayed on average for 6.2 months, while those who left temporarily in order to study spent on average 5.1 months abroad.

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In 2015, Poland was the most common country of previous residence of short-term migrants according to the 1 to 12 months definition, while Romania was the most common country of previous residence for the 3 to 12 months definition

The main sources of short-term migrants to England and Wales in 2015 were the Poland, USA, India, Australia and Spain (using the last country of residence as the indicator, 1 to 12 months definition). In the case of Poland, there was a large increase in the in-flow of short-term migrants from mid-2004 (see Figure 4), reaching a peak in the year to mid-2006 (221,000 short-term migrants from Poland). Since its peak, the number of short-term migrants from Poland has been on a downward trend.

Using the 3 to 12 months definition, the top countries of previous residence for short-term migrants in 2015 were Romania, India, Poland, France and the USA. The population of short-term migrants presents a somewhat similar pattern to the inflows in regards to the last country of residence. India and Romania lead the group with a population of about 14,000 short-term migrants each in 2015.

Table 4 – Top countries of previous residence for short-term migrants, 2015

 AustraliaPolandFranceUSASpainIndia
Mid-2015808972877782

In the year ending in mid-2015, 33% of all non-British short-term migrants came to the UK for work and 25% for study. However, when comparing the shares of those coming for work reasons across different nationalities, EU nationals are more likely to come for work reasons than non-EU nationals, especially in the 3-12 months definition. In the year to mid-2015, 52% of short-term EU nationals came for work reasons, compared to 11% among non-EU nationals. Among nationals of Romania and Bulgaria, 83% of short-term migrants came for work. Approximately 19% of EU nationals and 31% of non-EU nationals came for short-term study reasons in YE mid-2015.

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Newham was the top local authority in terms of the number of 3-12 month short-term migrants for study or work in 2015, followed by Manchester and Birmingham

Using the UN definition of short-term migrants, it is also possible to compare short-term migration across local authorities and regions in England and Wales. According to the UN definition of short-term migration (3 to 12 months for work or study), the inflow of short-term migrants to England and Wales in the year to mid-2015 was about 157,500. As might be expected, the region with the highest number of short-term migrants has consistently been London (at least since 2008); in the year to mid-2015, there was an inflow of 53,500 short-term migrants to London. In the same period, London was followed by the South East and East of England.

Figure 4

The top local authority in terms of the number of UN-defined short-term migrants was the borough of Newham in London, with an inflow of 4,600 (see Figure 6). Outside of London, the top local authorities were Manchester (3,700) and Birmingham (3,700).

Evidence gaps and limitations

The ONS has been comparing results for two definitions of a short-term migrant: 1) an individual who moves from (to) outside the UK to (from) England or Wales for 1-12 months and 2) an individual who moves from (to) outside the UK to (from) England or Wales for 3-12 months. There is no information available for international short-term moves to and from Scotland and Northern Ireland.

Drawing mainly on data from the IPS, the ONS’s short-term migration estimates rely on interviews at the end of the migrants’ stay. In contrast, information collected at the start of the migration process is the base of ONS estimates of long-term international migration.

The following example illustrates the necessary assumptions and limitations of the estimation of short-term migration: assume that only three short-term migrants (3-12 months definition) enter the UK in a given year. Short-term migrant number one stays for 120 days, short-term migrant number two stays for 120 days and short-term migrant number three stays for 125 days. In this example, the in-flow of short-term migrants is equal to 3 because three migrants entered the country and all stayed more than 3 months but less than 12 months. For the whole year, the in-stock is 1, because on average there is one migrant present for the whole year. This number comes from adding the stay of the three migrants in terms of days (120 + 120 + 125) and dividing by 365. The ONS refers to this estimate as the Long-Term Migrant Equivalent (ONS 2007). The estimate provides a number based on person years that is equivalent to long-term migration stays. If short-term migrant number three stays for 150 days, but only 125 of those days fall in the year under consideration, the short-term migration in-stock estimates for that year will not change. The additional 25 days will count in the short-term migration in-stock estimates of another year.

In order to estimate the average length of stay, the ONS adds all the days spent in the UK by migrants that entered in a certain year and divides this total by the number of migrants. For example, using the previous example of three short-term migrants, they would add the number of days (divided by 30 in order to express the days in months), that is: (120/30 + 120/30 + 125/30) = 12.17. Then this number would be divided by the number of short-term migrants (3), that is 12.17/3 = 4.1. Therefore, the average length of stay in this example is 4.1 months. Moreover, the average length of stay only accounts for short-term migrants who began their visit in the year of interest, regardless of the year of completion. Hence, if short-term migrant number three stays for 150 days, then all of those days would enter the average length estimate even if 25 of those days fall in the following year.

References

  • Office for National Statistics. “Research Report on Short-term Migration.” ONS, London, 2007.
  • Office for National Statistics. “Short Term Migration Estimates for England and Wales, Mid-2015 Estimates.” ONS, London, 2017.
  • Office for National Statistics. “Note on the difference between National Insurance number registrations and the estimate of long-term international migration: 2016.” ONS, London, 2016.

Thanks to Alessio Cangiano and Simon Whitworth for helpful comments and suggestions in an earlier version of this briefing.

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June 21, 2018

Author

Dr Carlos Vargas-Silva

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