Note: Based on the 3-12 months definition. The reference period is year to mid.
Short-Term Migration in the UK: A Discussion of the Issues and Existing Data
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.
Related documents
Key Points
- The ONS publishes short-term migration estimates for England and Wales, using two definitions of a short-term migrant: those staying for a minimum of one month or 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 about 1 million migrants in the year to mid-2010, while the 3 to 12 months definition puts the number at 214,000 migrants.
More... - Employment and study reasons in England and Wales account for about half of 3-12 months short-term migration. Employment reasons have become less important over time, while study reasons have become more important.
More... - Employment and study reasons in England and Wales account for almost half of 3-12 months migration. Employment reasons have become less important over time, while study reasons have become more important.
More... - The estimates suggest an in-stock (the number of short-term migrants residing in England and Wales) of about 193,000 short-term migrants in the year to mid-2010 for the 1 to 12 months definition and about 90,000 for the 3 to 12 months definition.
More... - The out-flow of short-term migrants (3 to 12 months definition) in the year to mid-2010 was 388,000 and the estimated out-stock was 153,000.
More... - The USA is the most common country of previous residence of short-term migrants (inflow of 96,000 in the year to mid-2010).
More...
The UK Office for National Statistics (ONS) reports data on short-term migrants defined as someone staying in the UK for less than a year, and at least one month. However, this is complicated by a number of factors involving how you measure migrant numbers – not least understanding that many holiday makers and business travellers are covered by this definition.
The data used in this briefing come from the ONS Mid-2010 Short-Term Migration Estimates for England and Wales. These refer to “year to mid” estimates - for instance, the figures for 2010 reflect year from mid-2009 to mid-2010 estimates. 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. 2010 short-term migration estimates are still provisional and subject to revisions.
Most of the UK’s migration statistics provided by the 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. The lack of data on migrants intending to stay for less than 12 months is widely recognised as a major problem.
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.
The ONS provides estimates of short-term in-flows of migrants (and out-flows of UK residents) and in-stocks of migrants (and out-stocks of UK residents). The term in-flow 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). In-stock denotes the stock of short-term migrants present in the UK during a specified period (number based on person years). See the Evidence gaps and limitations section for further details.
Short-term migration in-flows have been decreasing since the year to mid-2006
Figure 1 suggests that short-term migration in-flows to England and Wales have fallen since mid-2006, in both, the 1 to 12 months stay definition and the 3 to 12 months stay definition. Figure 1 also suggests that there is a significant difference between the two estimates. While the 1 to 12 months definition suggests a short-term migration in-flow of about 1 million, the 3 to 12 months definition puts the number at 214,000.
Figure 1
Employment and study reasons in England and Wales account for about half of 3-12 months stays
Figure 2 reports short-term migrants’ reasons for coming to England and Wales based on data for 2010, using the 3 to 12 months definition. These data suggest that about 32% of short-term migrants come for study purposes; in particular, many of them are likely to come for short-term English courses. Around 22% comes for employment in England and Wales, while the rest (46%) come for other reasons. The other reasons category may include leisure, visiting friends or family and doing business. Looking at the number of short-term migrants coming for study or work purposes is important because these two groups form the United Nations definition of short-term migration.
Figure 2
A look at the shares over time suggests that there has been a marked decrease in the share of short-term migrants that are coming for employment related reasons (from 29% in 2006 to just 22% in 2010), and an increase in those coming for study reasons (from 22% in 2006 to 32% in 2010).
The short-term migration in-stock increased from 2004 to 2006, but has been decreasing since then
As shown in Figure 3, the migration in-stock increased from 2004 to 2006 and has been decreasing since then. The figures indicate an in-stock of about 193,000 for the 1 to 12 months definition and about 90,000 for the 3 to 12 months definition in the year to mid-2010.
Figure 3
Among those staying for 3-12 months, the mean length of stay is 5.1 months (see Table 1). Table 2 looks at the distribution of the in-stock by the reason for coming to England and Wales, and suggests that for the 3 to 12 months definition the distribution according to reasons for visit for the in-stock is similar to that of the in-flow. About 20% stated employment related reasons, 36% stated study reasons and about 44% stated other reasons. Those moving for study reasons are staying slightly longer (5.5 months in the year to mid-2010) than those moving for other reasons (4.8 months) (Table 1).
Table 1 - Mean length of stay for the in-stock by reason for visit for the different definitions (in months) for 2010
Table 2 - Shares of in-flow and in-stock by reason for different definitions for 2007, 2008 and 2009
There has been a decrease in the share of the in-stock of short-term migrants that come for employment purposes (from 32% in 2006 to 20% in 2010, 3 to 12 months definition), and a increase in the share that come for study purposes (from 22% in 2006 to 36% in 2010).
The out-flow and out-stock of short-term migrants are higher than in-flow and in-stock
The estimates of short-term migration out-flow and the out-stock refer to individuals who are usually resident in England and Wales making short-term visits abroad. Figure 4 reports the out-flow and out-stock series for the 3 to 12 months definition. The out-flow and out-stock of short-term migrants in the year to mid-2010 were 388,000 and 153,000, respectively. Therefore, the short-term migration out-flow and out-stock exceed the short-term in-flow and in-stock. It is not straightforward to talk about net short-term migration, as it is to talk about long-term net migration, given that these estimates refer to short-term moves within a year.
Figure 4
In terms of the mean length of time abroad for the out-stock (3-12 months), the mean length of stay was 4.7 months in the year to mid-2010, which is a bit less than for the in-stock.
The USA was the most common country of previous residence of short-term migrants in 2010
The main sources of short-term migrants to England and Wales in 2010 were USA, Poland, Australia, India 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 5), reaching a peak in the year to mid-2006 (221,000 short-term migrants from Poland). However, there has been a decrease in the number of short-term migrants from Poland during the last few years (the inflow was 84,000 short-term migrants from Poland in the year to mid-2010).
The in-stock of migrants presents a somewhat similar pattern in regards to the last country of residence. India and Poland lead the group with a stock of about 17,000 short-term migrants each in the year to mid-2010.
Figure 5
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 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 3 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 divide 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 3 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-2010 Estimates.” ONS, London, 2012.
Thanks to Alessio Cangiano and Simon Whitworth for helpful comments and suggestions in an earlier version of this briefing.
