Population estimates by output areas, electoral, health and other geographies, England and Wales: mid-2017

• There continues to be wide variations in the age structure of the population across England and Wales, with coastal and rural areas tending to have older populations than cities and urban areas.
• In mid-2017, the Lower layer Super Output Area (LSOA) with the highest median age was Eastbourne 012B at 70.8 years, whereas Salford 016E had the lowest median age at 14.7 years; across all of England and Wales the median age was 39.9 years.
• The proportion of people aged over 65 years living in areas served by different clinical commissioning groups (CCGs) in England ranged from 6.2% in Tower Hamlets to 29.6% in NHS North Norfolk (across England 18.0% of the population are aged 65 years or over).
• English Parliamentary constituencies tend to have larger populations than Welsh constituencies (averages of 104,352 and 78,129, respectively).
• While the average electoral ward in England and Wales had a mean population of 7,065, population sizes ranged from 162 in St. Martin’s ward in the Isles of Scilly to 43,359 in City and Hunslet ward in Leeds.
• This bulletin incorporates the release of small area population estimates for mid-2012 to mid-2016 revised to be consistent with the March 2018 revisions to mid-year population estimates.

This bulletin includes estimates for Lower and Middle layer Super Output Areas (LSOAs and MSOAs), Westminster Parliamentary constituencies and electoral wards and National Parks in England and Wales, and clinical commissioning groups (CCGs) in England.

This publication includes the first release of data for mid-2017 and revisions to data for mid-2012 to mid-2016. The data published in this release for mid-2012 to mid-2016 supersede the previous series of small area population estimates for this period. The Quality and Methodology Information (QMI) report and the Methodology guide accompanying this release set out the changes that have occurred in more detail and explain why these changes have been made now.

What’s changed

Small area population estimates have been revised to account for revisions made to local authority population estimates for England and Wales made in March 2018. The changes to the local authority estimates were:

• local authority emigration estimates for mid-2012 to mid-2016 have been recalculated using an improved distribution model that includes a wider range of administrative and survey data than before
• local authority-level immigration estimates for mid-2015 and mid-2016 have been recompiled using previously unavailable data and using improved matching methods to better distinguish students, workers and other international in-migrants
• an improved method for accounting for the migration of dependants of foreign armed forces personnel has been incorporated; this results in improvements to the population estimates of Forest Heath and other local authorities containing, or neighbouring, US Air Force base
• minor changes have also been made to ensure methods have been implemented consistently across years – specifically for mid-2012 and mid-2013 age distributions of asylum seekers and emigrants, and to the adjustment made between Coventry and Warwick student locations in mid-2014 and mid-2015

The geographies used in the small area estimates have been made consistent for each year between mid-2012 and mid-2017; the latest available boundaries have been used.

What’s not changed

The following were not affected by the March 2018 revisions:

• population totals for each single year of age and sex are unchanged for both England and Wales, only subnational estimates have changed
• definitions, such as these estimates covering the usually resident population at 30 June each year, are unchanged and can be found in the QMI

There are two broad types of small area population estimates, both of which are included in this release.

The main products are the estimates for Super Output Areas (SOAs), which are based on the 2011 Census and rolled forward annually using a ratio change methodology. This approach uses the change in the population recorded in the GP Patient Register as an indicator of the change in the true population. Estimates for Lower level Super Output Areas (LSOAs) by broad ages and Middle level Super Output Areas (MSOAs) by five-year age groups (quinary age) hold National Statistics status. Estimates at a greater level of disaggregation by age including quinary age for LSOAs and single year of age for both SOAs are supporting information only. More information can be found in small area population estimates: summary of methodology review and research update.

The remainder of the small area population estimates products relate to a range of different geographic areas and are derived directly from the SOA figures. Firstly, estimates for LSOAs are broken down to Output Area (OA) level using an apportionment approach. These OA estimates are then aggregated to produce estimates for electoral wards and Westminster Parliamentary constituencies on a best-fit basis. Estimates for national parks are also calculated from the OA-level data. Electoral wards, Westminster Parliamentary constituencies and National Parks all hold Experimental Statistics status. Estimates for health geographies are aggregated directly from LSOAs and hold National Statistics status.

Small area population estimates are used by both central government departments and local authorities for a range of purposes, including planning and monitoring of services and as denominators for the calculation of various rates and indicators. The Quality and Methodology Information report has further information on the quality and use of these statistics.

Population estimates for LSOAs and MSOAs are often used for research and analysis as, unlike other small area geographies, such as electoral wards, they are specifically designed for statistical purposes. Electoral ward population estimates are of particular interest to local government organisations. Parliamentary constituency estimates are of importance to Parliamentary organisations, researchers and MPs. Population estimates for health geographies are widely used within the health sector and information on National Parks is valuable to both local government and the various National Park authorities.

The mid-2012 to mid-2017 small area population estimates covered by this bulletin are fully consistent with population estimates for higher levels of geography including local authorities, regions and the national total for England and Wales. A full description of the methods used to calculate all small area population estimates is available in the methodology guide.

In some local authorities, the number of people included in the Patient Register data in 2017 has increased or decreased in a large number of LSOAs and MSOAs compared with 2016 data, which may be due to changes in administrative practices or may reflect genuine population change. The process of constraining LSOA and MSOA estimates to previously published local authority population estimates means that this pattern is not automatically reflected in the mid-year estimates.

Mid-year population estimates for 2017 for England and Wales, regions within England and local authorities within England and Wales were published on 28 June 2018. The estimates refer to the usually resident population on 30 June of the reference year and are published annually. In mid-2017, the population of England and Wales was 58,744,595, an increase of 0.6% since mid-2016 and 8.0% over the 10 years since mid-2007.

The population increase of 363,400 since mid-2016 was driven by net international migration of 215,700 and natural change (births minus deaths) of 155,900 and offset slightly by internal migration of -11,000. Other changes of 2,900 made up the remaining increase. The population of England and Wales is ageing. Ageing of the population refers to both the increase in the average (median) age of the population and the increase in the number and proportion of older people in the population. The proportion of the population in England and Wales aged 65 years or over at mid-2017 was 18.2%, compared with 15.9% at mid-2007. Changes in the population of England and Wales are reflected in the changes at small area levels outlined throughout this bulletin.

Super Output Area (SOA) population estimates comprise:

• National Statistics for Lower layer Super Output Areas (LSOAs) by broad age groups and Middle layer Super Output Areas (MSOAs) by five-year age groups (quinary ages)
• supporting information for estimates at a greater level of disaggregation by age, including quinary age for LSOAs and single year of age for both SOAs

The age structures of populations at a local level can vary widely indicating different requirements for public services provision. The age structure of the two areas with the highest (MSOA Eastbourne 12) and lowest (MSOA Salford 16) median ages are shown in Figure 1. In mid-2017 in Salford 16, there were 20.4% of the population aged 0 to 9 years and 7% aged over 70 years; in Eastbourne 12, there were 5.6% aged 0 to 9 years and 35% aged 70 years or over. More generally these age structures typify many of the features of coastal populations (Eastbourne) and multicultural urban populations (Salford).

Populations in coastal areas, National Parks and the South West have older age structures

Population statistics at LSOA and MSOA level provide insight into how the age structures of populations vary at a local level. For example, while the median age of the population of England and Wales in mid-2017 was 39.9 years, the median age for LSOAs within England and Wales varied widely, from a high of 70.8 years in Eastbourne 012B to a low of 14.7 years in Salford 16E. Median age is the age that divides a population into two numerically equal groups – that is, half the people are younger than this age and half are older. Median age provides a useful summary measure of the age structure of the population. Figure 2 shows that populations with the highest median age are concentrated around the coastal areas, the National Parks and the South West.

Figure 2: Highest median age (top 5%), by Lower layer Super Output Areas, England and Wales, mid-2017

Source: Office for National Statistics

Download this image Figure 2: Highest median age (top 5%), by Lower layer Super Output Areas, England and Wales, mid-2017

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Figure 3 shows the percentage change in population between mid-2016 and mid-2017 for MSOAs in England and Wales. This echoes many of the same patterns of change seen at the local authority level, notably, that population growth across England and Wales was more even in the year to mid-2017 compared with recent years, where growth in many parts of London and other large cities was higher than in many coastal and rural areas. The more even pattern of growth compared with last year is due partly to lower levels of net international migration between mid-2016 and mid-2017.

Further, Figure 3 shows that within local authorities, patterns of growth can vary widely, with adjacent areas often experiencing contrasting population change. For example, in Greater London there are a number of areas which had relatively high levels of population growth adjoining nearby areas with falling populations.

Figure 3: Percentage change in population by Middle layer Super Output Areas, England and Wales, mid-2016 to mid-2017

Source: Office for National Statistics

Download this image Figure 3: Percentage change in population by Middle layer Super Output Areas, England and Wales, mid-2016 to mid-2017

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Small area population estimates for mid-2012 to mid-2016 have been revised in light of the changes to local authority population estimates made in March 2018. For the most part the changes seen at the local authority level are reflected directly in small area estimates. If a local authority estimate for an age or sex group was revised upwards by 2% then the estimates for that age or sex group for Output Areas (OAs), Lower level Super Output Areas (LSOAs) and Middle level Super Output Areas (MSOAs) would be revised upwards by around 2%. Tables 1 and 2 show the local authority areas that experienced the largest revisions of more than 1% to their population estimates. The Quality and Methodology Information (QMI) report and the Methodology guide accompanying this release set out the changes that have occurred in more detail.

Figure 4 is an interactive tool that shows the percentage impact of revisions for broad age groups at LSOA level for mid-2016. You can either enter the postcode of a small area you are interested, use your current location or scroll around the map.

Figure 4: Comparison of mid-2016 revised and un-revised LSOA population estimates by broad age group

Clinical commissioning groups (CCGs) are responsible for deciding how NHS funds are spent in their local area. They were introduced, for England only, by the Health and Social Care Act 2012 as part of a new structure for NHS organisation, which came into force on 1 April 2013.

CCGs replaced the former health geography areas, known as Primary Care Organisations (PCOs). Following a formal consultation we discontinued the production of population estimates for PCOs.

The mid-2017 CCG population estimates, referred to in this bulletin, are direct aggregations of mid-2017 Lower layer Super Output Area (LSOA) estimates. They are consistent with population estimates for the national total for England. These estimates are classified as National Statistics.

CCGs are organised into the higher level of health geography of NHS England (Region, Local office) and NHS England (Region). These geographies are formed from groups of CCGs and therefore population estimates for these areas are also created by directly aggregating Lower level Super Output Area (LSOA) estimates.

As 1 April 2017, there were 195 CCGs, 14 NHS England Region Local offices and five NHS England Regions. At mid-2017, the mean population of CCGs was 285,228 with population sizes ranging from 69,540 in NHS Corby CCG to over 1.175 million in NHS Birmingham and Solihull CCG.

CCGs in London experience slower population growth than in recent years

Of the 10 CCGs with the largest percentage increases in population between mid-2016 and mid-2017, four were in London; in the previous year to mid-2016, six of the fastest-growing CCG populations were in London. The CCG with the largest percentage increase in population was NHS Tower Hamlets at 2.3%.

Only 11 CCGs had a population decrease between mid-2016 and mid-2017, with the greatest decreases being 0.6% in NHS Ealing CCG, NHS Luton CCG and NHS West London CCG.

Wide variation in age structure of population across CCGs

The age distribution of the resident population in a CCG is likely to impact on both the overall level of demand for health services and the type of health services required. Areas with a large percentage of older people in their population are likely to have different demands on health services than those with younger populations.

In mid-2017, the population of England aged 65 years or over was 18.0%. By comparison, the population in NHS North Norfolk CCG aged 65 years or over was 29.6%. Figure 5 shows the percentage of the population aged 65 years or over by CCG. CCGs in more rural and coastal areas tend to serve higher proportions of older people than those in London and other metropolitan areas. In mid-2017, the CCG with the lowest proportion of people aged 65 years or older was NHS Tower Hamlets CCG (6.2%).

Figure 5: Percentage of population aged 65 years or over, by clinical commissioning group, England, mid-2017

Source: Office for National Statistics

Download this image Figure 5: Percentage of population aged 65 years or over, by clinical commissioning group, England, mid-2017

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The percentage of the population who are children may also impact on requirements for health service provision. In mid-2017, the population of England aged 0 to 15 years was 19.1%. By comparison, 28.0% of the population in NHS Bradford City CCG were aged 0 to 15 years, closely followed by NHS Barking and Dagenham CCG (27.3%). As Figure 6 shows, CCGs with high proportions of children tend to be in more urban areas of England, while many rural and coastal areas have relatively low proportions of children.

Figure 6 shows the percentage of the population aged 0 to 15 years by CCG.

Figure 6: Percentage of population aged 0 to 15 years, by clinical commissioning group, England, mid-2017

Source: Office for National Statistics

Download this image Figure 6: Percentage of population aged 0 to 15 years, by clinical commissioning group, England, mid-2017

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At mid-2017, the mean population of Parliamentary constituencies in England and Wales was 102,521 with population sizes ranging from 58,941 in Aberconwy to 185,200 in West Ham. On average, English constituencies have larger populations than Welsh constituencies, with mean populations of 104,352 and 78,129, respectively.

Westminster Parliamentary constituencies are the areas used to elect Members of Parliament (MPs) to the House of Commons, the primary legislative chamber of the UK. The current boundaries were introduced for the May 2010 General Election and include 533 constituencies in England and 40 in Wales. Parliamentary constituency estimates are classified as Experimental Statistics.

Annual population change

Parliamentary constituencies with the greatest increases in population over the one-year period were more evenly spread across England and Wales in the year to mid-2017 than in recent years. As in the year to mid-2016 the area with the greatest increase was Manchester Central at 2.8%.

Population decreases at Parliamentary constituency level occurred across the country and four constituencies saw population decreases of 1% of more: Luton North, Ealing North, Mitcham and Morden, and Hornsey and Wood Green.

Wide variation in age structure of population across Parliamentary constituencies

Figure 7 shows how the median age of the population varies across the 573 Parliamentary constituencies in England and Wales. In London and the majority of other urban areas across England and Wales, the median age tends to be lower than in the more rural and coastal areas. In 2017, Sheffield Central had the lowest median age (just over 26 years) and Christchurch and North Norfolk both had median ages above 53 years.

Figure 7: Median age of population by Westminster Parliamentary constituency, England and Wales, mid-2017

Source: Office for National Statistics

Download this image Figure 7: Median age of population by Westminster Parliamentary constituency, England and Wales, mid-2017

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Voting age

In England and Wales in mid-2017, there were 46,249,349 persons aged 18 years and over, making up 78.7% of the total usual resident population. In mid-2017, at Parliamentary constituency level, the percentage of the population aged 18 years and over ranged from 67% in Birmingham, Hodge Hill to 87% in Liverpool, Riverside.

The population of voting age in a Parliamentary constituency is not the same as the population who are entitled to vote, as it includes people who are not eligible to vote. For example, European Union citizens (excluding British citizens; and Irish, Cypriot and Maltese citizens who are qualifying Commonwealth citizens) are not entitled to vote in Westminster Parliamentary elections, but are entitled to vote in local elections and are included in the population estimates if they are resident in the UK for 12 months or more.

Electoral statistics, providing counts of the number of persons registered to vote in each Parliamentary constituency, are available.

Electoral wards are an important building block of UK administrative geography. They are the spatial units used to elect local government councillors in metropolitan and non-metropolitan districts, unitary authorities and London boroughs in England, and unitary authorities in Wales. In some unitary authorities in England they are legally termed as “electoral divisions”, however, they are frequently referred to as wards and are referenced as such throughout this bulletin. The five parishes of the Isles of Scilly are also treated as electoral wards for statistical purposes.

Electoral wards are subject to annual updates and boundary changes that make comparisons over longer periods more difficult. Mid-2017 population estimates are provided for 8,297 electoral wards in England and Wales as at 31 December 2016, excluding the 18 wards that do not meet the minimum population requirements for data confidentiality (40 resident households and 100 resident people in the 2011 Census). Electoral ward estimates are classified as Experimental Statistics.

At mid-2017, the mean population of wards in England and Wales was 7,065. However, population sizes vary widely across the country ranging from 162 in St. Martin’s ward in the Isles of Scilly to 43,359 in City and Hunslet ward in Leeds. On average, wards in England have larger populations than those in Wales, with mean populations of 7,453 and 3,669, respectively. Figure 8 shows that 58.3% of electoral wards in Wales have populations of less than 3,000, compared with 16.1% of wards in England, and a further 21.5% of wards in England have populations of 11,000 or higher compared with 3.4% of wards in Wales.

National Parks are designated areas of protected countryside aimed at conserving the natural beauty, wildlife and cultural heritage of the area. Each National Park has a National Park Authority (NPA) responsible for conservation, planning, recreation management and fostering the social and economic well-being of local communities.

The Broads Authority does not have a National Park designation, but is included in this set of statistics, as it is part of the National Parks family. The Broads Authority has similar responsibilities to NPAs, but with additional powers relating to navigation. In total there are 13 National Parks in England and Wales (including The Broads Authority) (Figure 9).

National Park population estimates are classified as Experimental Statistics.

Figure 9: National Parks in England and Wales

Source: Office for National Statistics

Download this image Figure 9: National Parks in England and Wales

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National Parks have an older age structure than the wider population of England and Wales. In mid-2017, the median age for National Parks within England and Wales varied from 48.6 years in the South Downs to 56.8 years in Exmoor. In contrast, the median age for England and Wales as a whole was 39.9 years.

Table 3 gives a summary of the main features of National Park populations. It shows that all 13 National Parks have a larger proportion of the population aged 65 years or over than England and Wales as a whole. In mid-2017, the population of England and Wales aged 65 years or over was 18.2%, compared with 24.2% in Northumberland, 34.4% in Exmoor and 33.9% in The Broads Authority. Conversely, 19.1% of the population in England and Wales were aged 0 to 15 years compared with only 10.7% in The Broads Authority and 11.4% in Exmoor.

Population density, that is, the number of people living per square kilometre, can be used to highlight how sparsely populated National Parks are in comparison with more urban population settlements. In mid-2017, the population density of England and Wales was 389 persons per square kilometre. Northumberland National Park is the most sparsely populated area with a population density of two persons per square kilometre and the South Downs is the most densely populated area with 71 persons per square kilometre.

Population estimates are produced for similar small areas in both Scotland and Northern Ireland, however, they are not produced using the same methodology as for small area population estimates in England and Wales.

National Records of Scotland (NRS) produce population estimates for Scottish data zones, which are slightly smaller areas than Lower layer Super Output Areas (LSOAs), designed to contain approximately 500 to 1,000 household residents. NRS use a cohort component-based method to produce estimates for data zones, further information on this methodology and the latest estimates (for mid-2017) are available from their website.

The Scottish data zones are used to produce population estimates for a range of other geographies including Westminster Parliamentary constituencies in Scotland, Scottish Parliamentary constituencies and Nomenclature of Units for Territorial Statistics (the statistical geography used by the European Union). These figures are available from the Special Area Population Estimates section of the NRS website.

The Northern Ireland Statistics and Research Agency (NISRA) publish population estimates for Super Output Areas in Northern Ireland. These are of similar size to English and Welsh LSOAs, with an average population of 2,100. NISRA uses a mixed methodology based on both cohort component and ratio change approaches. Further information and the latest estimates published for mid-2016 are available from the NISRA website. Population estimates for wards, Neighbourhood Renewal Areas and Census Small Areas in Northern Ireland are also available.

A paper, Small Area Population Estimates across the UK, which provides a broad description of the different methodologies used to produce small area population estimates in each constituent country of the UK, is also available on the NISRA website.

This statistical bulletin is part of our Small area population estimates in England and Wales: mid-2017. The publication includes:

• population estimates for Lower and Middle layer Super Output Areas (LSOAs and MSOAs) in England and Wales; estimates for LSOAs by broad ages and MSOAs by five-year age groups (quinary age) hold National Statistics status; estimates at a greater level of disaggregation by age including quinary age for LSOAs and single year of age for both SOAs are supporting information only; more information can be found in Small Area Population Estimates: Summary of methodology review and research update
• population estimates for electoral wards, Westminster Parliamentary constituencies and National Parks in England and Wales – these products are classified as Experimental Statistics
• population estimates for health geographies in England (clinical commissioning groups (CCGs), NHS England (Region, Local office) and NHS England (Region)) – these products are also classified as National Statistics

These estimates are consistent with the results of the 2011 Census and are provided for the latest official geographic boundaries in place at the time of publication.

Other related statistics:

• an overview of the UK population is available
• mid-2017 population estimates for small area geographies in England and Wales are available from the data section of this release
• mid-2017 population estimates for the UK and its constituent countries, regions and local authorities are also available

News on our population statistics can be obtained by subscribing to the quarterly newsletter (email your request to population.statistics@ons.gov.uk) or following the Twitter account @RichPereira_ONS

The Small area population estimates Quality and Methodology Information report contains important information on:

• the strengths and limitations of the data
• the quality of the output: including the accuracy of the data and how it compares with related data
• uses and users
• how the output was created

A Methodology note on production of small area population estimates details the data sources and methodology applied to producing the England and Wales small area population estimates.

The report Small Area Population Estimates (SAPE) Evaluation: Report on Accuracy Compared to Results of the 2011 Census presents research that evaluates the accuracy of the small area population estimates to inform their broad variety of users. The report also fulfils the commitment to analysis planned after the 2011 Census.

The ONS Revisions Policy on population statistics, including the small area population estimates, explains how we implement and categorise revisions to statistics, including following a census.