The estimated population of an area includes all those usually resident there, whatever their nationality. Students are treated as being resident at their term-time address. Members of UK and non-UK armed forces stationed in Scotland are included; UK forces stationed outside Scotland are excluded. Short-term international migrants are excluded.
Population figures relate to 30 June of the year shown and ages relate to age last birthday.
Although the populations are tabulated in units, this does not imply accuracy to that level. The data are presented in units for the convenience of users wishing to compile non-standard aggregations without encountering rounding problems.
The composition of the NHS Board areas in terms of Council areas is summarised in the table below. From 1 April 2006 responsibility for NHS Argyll & Clyde was split between NHS Greater Glasgow (now known as Greater Glasgow and Clyde) and NHS Highland. The tables presented in this report present information for the new NHS Board areas, but also show data for the relevant component parts of NHS Argyll & Clyde.
Composition of NHS Board areas
NHS Board area |
Council area |
|---|---|
Ayrshire & Arran |
East Ayrshire, North Ayrshire, South Ayrshire |
Borders |
Scottish Borders |
Dumfries & Galloway |
Dumfries & Galloway |
Fife |
Fife |
Forth Valley |
Clackmannanshire, Falkirk (part), Stirling (part), Perth & Kinross (part) |
Grampian |
Aberdeen City, Aberdeenshire, Moray |
Greater Glasgow & Clyde1 |
East Dunbartonshire, East Renfrewshire, Glasgow City, Inverclyde, North Lanarkshire (part), Renfrewshire, South Lanarkshire (part), Stirling (part), West Dunbartonshire |
Highland1 |
Highland, Argyll & Bute |
Lanarkshire |
North Lanarkshire (part), South Lanarkshire (part), West Lothian (part), Falkirk (part) |
Lothian |
East Lothian, City of Edinburgh, Midlothian, West Lothian (part), Falkirk (part) |
Orkney |
Orkney Islands |
Shetland |
Shetland Islands |
Tayside |
Angus, Dundee City, Perth & Kinross (part) |
Western Isles |
Eilean Siar |
1 New NHS Board areas including parts of former Argyll & Clyde.
Note: In practice there are some other very small "slivers" where NHS Board and Council area boundaries cross.
The land areas used to calculate the population density information presented in Table 9 were derived from digital boundaries used for the 2001 Census.
Migration is the most difficult component of population change to estimate. The other components (births and deaths) are estimated using data from the civil registration system, which is considered to be virtually complete. In contrast, there is no comprehensive system which registers migration in the UK - either moves to or from the rest of the world, or moves within the UK. Estimates of migration therefore have to be based on survey data and the best proxy data that exist.
Migration is derived from three key sources of data. The National Health Service Central Register (NHSCR) for moves between health board areas within the UK, with migration at council area level within Scotland estimated using anonymised data from the Community Health Index (CHI). The International Passenger Survey (IPS) provides information on moves into and out of Scotland from outside the UK.
The NHSCR system records the movements of patients between NHS health board areas in the UK. Each time a patient transfers to a new NHS doctor in a different health board area, the NHSCR is notified and then the patient is considered to have made a migrant move. Counts of these re-registrations are used as a proxy indicator for moves within the UK.
The CHI holds records of people registered with an NHS doctor in Scotland. Unlike the NHSCR, the records provided to GROS contain the postcode of the patient's address, which enables migration to be estimated for councils, and for smaller areas. The approach used for estimating council-level migration involves matching CHI patient records which are extracted from a database which reflects the ‘live’ CHI system on two occasions one year apart. This matching of two extracts, say A and B, will create three sets of patients:
1. patients in extract A and extract B;
2. patients in extract A but not in extract B;
3. patients in extract B but not in extract A.
Patients in both extracts A and B (set 1) whose postcodes are not the same in each extract can be considered as those within-Scotland migrants who moved from one address in Scotland to another within Scotland between the dates of the two extracts. Patients in sets 2 and 3 are either migrants to or from Scotland; babies born between the two extracts; deaths between the dates of the two extracts; movements to or from the Armed Forces; and a small number of records that are for the same patient but have different CHI numbers because they could not be matched when the GP registration was processed.
Currently, GROS migration data derived from the NHSCR is considered to be the most reliable data available at health board level, so estimates from the CHI are controlled to ensure that they are consistent with the NHSCR data for moves across a health board boundary by origin, destination, age and sex.
The International Passenger Survey (IPS) is a continuous sample survey conducted by the Office for National Statistics at the principal air, sea and Channel Tunnel routes between the UK and countries outside the British Isles. The sample of migrants contacted within the survey is small, particularly for Scottish migrants (around 140 survey contacts for Scotland in 2006), and therefore estimates derived from the IPS are subject to larger sampling and non-sampling errors, and are considered less reliable than UK-level estimates. Information about the country of origin and destination, and age of migrants is particularly subject to error. In addition to IPS data, additional information is received on migrants to and from the Republic of Ireland, asylum seekers and visitor switchers3.
The method for estimating international migration into and out of Scotland combines data on intentions to migrate to Scotland based on the IPS, along with estimates of data on migration from Ireland, visitor switchers3 and asylum seekers. An estimate for unmeasured migration is also included and this is explained in more detail below.
The Office for National Statistics (ONS) produce an estimate of Total International Migration (TIM) which is similar to this approach, although it includes an adjustment for migrant switchers (people who intend to stay for one year but stay for a shorter period), and use a modified methodology for visitor switchers. More information on the ONS method can be found in their publication Total International Migration 2005 which is available on their website.
Research has been carried out through the National Statistics Quality Review of International Migration and, latterly, the ONS Improving Population and Migration Statistics (IMPS) project, which is available on their website.
As a result of this research ONS have revised the TIM methodology and a full description of the methodology can be found on the IMPS updates page on the previous link.
Given the completion of this research, GROS plan, over the summer, to carry out a full review of the methodology used to estimate international migration for the purposes of mid-year population estimates. An announcement on the conclusions of the review and the requirement for any revisions to the mid-year population estimates series will be made as soon as the evaluation has been completed.
For the mid-2006 population estimates, international migration to NHS Boards was allocated by using both overseas outflows and moves from Scotland to the rest of the UK recorded on the NHS Central Register (NHSCR). These averaged proportions were used to allocate international outflows from NHS Boards. The proportion of international inflows to NHS Boards in Scotland recorded on the NHSCR were used to allocate the international inflows.
The overseas inflow from the NHSCR was used to give an age and sex distribution to international in-migrants, while the age/sex distribution of moves to the rest of the UK recorded by the NHSCR was used for international out-migrants.
The issue of how international migration is allocated to NHS Boards will be considered further once the results of the work being carried out as part of the quality review into international migration are known.
The results of the 2001 Census indicated that the previously published 2000 mid-year estimates had been overestimated by some 50,000 as a result of cumulative errors in estimating migration (mostly by young men) during the 1980s and 1990s. As a result, the migration estimates for 1982-2000 were revised. It is likely that these migration errors were the result of an underestimation of young male migration from Scotland to the rest of the world during this period, but if moves from Scotland to the rest of the UK had been under-recorded, the implied increase in overseas migration would be less.
To ensure that migration estimates do not continue to be overestimated, an adjustment was included in the 2002 and 2003 mid-year estimates. The estimated civilian migration component included an adjustment for unmeasured migration. At the Scotland level, this amounted to an outflow of -2,600. Further investigation has shown that this adjustment should be -1,500 and this is the adjustment which has been used in the mid-2004 and subsequent estimates. It is planned to look at this element of unmeasured migration again in conjunction with other development work on migration. Further work will make it possible to provide historic estimates of flows between Scotland and the rest of the UK and overseas consistent with the revised population estimates. More information on the cumulative migration error since 1981 can be found in the "Comparison with Previous Estimates and Implications for Revisions" paper on our website, or by contacting our Statistics Customer Services.