Mid-Year Population Estimates for Wards, Parliamentary Constituencies and Health Geographies: Mid-2002 to Mid-2010

• Population estimates for health geographies, parliamentary constituencies and electoral wards for mid-2002 to mid-2010 have been revised following the 2011 Census.

• The revised series allows an understanding of how populations have changed across the decade in these small areas. An example of the type of analysis that is possible is shown in the statistical bulletin for revised mid-2002 to mid-2010 Super Output Areas.

• HS Tower Hamlets, NHS North Manchester and NHS Newham had the largest percentage increases in population between mid-2002 and mid-2011 (23.7%, 23.2% and 21.6% respectively).

• The two parliamentary constituencies with the largest percentage population increase were Manchester Central (30.7%) and Poplar and Limehouse (30.2%).

• Forty four per cent of wards saw population growth of more than 5% between mid-2002 and mid-2011.

• These small area estimates are particularly important for central government and local government for the planning and monitoring of services, as well as providing detailed information on the population of small local areas for parliamentary organisations, researchers and MPs, academics and commercial organisations.

This release presents the revised 2002 to 2010 mid-year population estimates for health geographies (clinical commissioning groups and former primary care organisations) in England; Westminster parliamentary constituencies and electoral wards in England and Wales. These estimates correspond to the revised population estimates for higher levels of geography including local authorities and regions and the national total for England and Wales.

A revised back series of lower layer and middle layer Super Output Areas (LSOA and MSOA) population estimates for mid-2002 to mid-2010 have also been published alongside this release.

In addition to the main local authority estimates for England and Wales, ONS publishes population estimates for small areas including Super Output Areas (SOAs), national parks, wards, parliamentary constituencies and health geographies.

To reflect the 2011 Census results, revised local authority population estimates were published on 30 April 2013. This release provides the corresponding revised population estimates for health geographies, parliamentary constituencies and electoral wards for mid-2002 to mid-2010. The revised series allows an understanding of how populations have changed across the decade in these small areas. An example of the type of analysis that is possible is shown in the statistical bulletin for revised mid-2002 to mid-2010 Super Output Areas.

Small area population estimates

Mid-year population estimates for health geographies, parliamentary constituencies and wards form part of a suite of small area population estimates for England and Wales. There are two main types of small area population estimates:

• Super Output Area (SOA) estimates – National Statistics including estimates for middle and lower layer SOAs.

• Estimates for other geographies – Experimental Statistics including estimates for parliamentary constituencies, wards and health geographies.

Health geographies

Clinical commissioning group (CCG) areas are formed from groups of lower layer Super Output Areas (LSOAs), which are a level of geography designed specifically for the reporting of small area statistics. There are 211 CCGs within England whose function is to commission healthcare services for their communities. CCGs replaced PCOs from 1 April 2013. For comparison purposes, revised estimates are also provided in the reference tables for the 151 former PCO areas.

Westminster parliamentary constituencies and wards

The revised mid-2002 to mid-2010 estimates for Westminster parliamentary constituencies are based on the constituency boundaries that were introduced for the May 2010 General Election. There are 573 constituencies in England and Wales.

Revised estimates for wards are based on 2012 electoral ward boundaries to provide a consistent series between mid-2002 and mid-2012. These estimates are provided for the 8,564 electoral wards in England and Wales as at 31 December 2012, excluding the 18 wards which do not meet the minimum population requirements for data confidentiality (40 resident households and 100 resident people in the 2011 Census). Both the parliamentary constituency and ward estimates, referred to in this bulletin, are aggregations of Output Areas (OAs). Revised mid-2002 to mid-2010 and mid-2011 to mid-2012 OA estimates are available as supporting information on the ad-hoc section of the ONS website.

In general, 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; as denominators for the calculation of various rates and indicators and as a base for population projections and forecasts. Specifically, parliamentary constituency population estimates are of particular interest to parliamentary organisations, researchers and MPs; ward estimates are of interest to local government organisations, academics and commercial organisations; and health geography estimates are of interest to the Department of Health and NHS organisations.

To reflect 2011 Census results, the mid-2002 to mid-2010 population estimates for health geographies, parliamentary constituencies and wards have been revised to correspond to the revised population estimates for local authorities and the national total for England and Wales.

The revised mid-2002 to mid-2010 health geography population estimates are derived from aggregating the revised lower layer Super Output Area (LSOA) estimates. Similarly, the revised mid-2002 to mid-2010 parliamentary constituency and ward estimates are derived from aggregating whole revised mid-2002 to mid-2010 Output Area (OA) estimates (based on the OA boundaries introduced for the publication of 2011 Census results). OA boundaries are not an exact fit (non-coterminous) for either ward or parliamentary constituency boundaries and therefore are allocated using a best-fit approach. The revised mid-2002 to mid-2010 OA estimates are constrained to the revised mid-2002 to mid-2010 LSOA estimates.

A full explanation of the methods used to revise these estimates is provided in the methods reports.

The next section of this release describes how much the other small area estimates have changed over the decade since mid-2002 as a result of revisions following the 2011 Census.

Clinical Commissioning Groups – change over the decade, mid-2002 to mid-2011

Map 1 below shows the percentage growth between the revised mid-2002 and mid-2011 clinical commissioning group (CCG) estimates for England.

NHS Tower Hamlets, NHS North Manchester and NHS Newham had the largest percentage increases in population between mid-2002 and mid-2011 (23.7%, 23.2% and 21.6% respectively). Nine CCGs had a population decrease between mid-2002 and mid-2011, although these decreases were small in percentage terms (between 0.1% and 3.7%). NHS Sefton had a decrease of 3.7% (-6,200 people) over the decade.

Map 1: Percentage population growth by clinical commissioning group, mid-2002 to mid-2011, England

Source: Office for National Statistics

Parliamentary constituencies – change over the decade, mid-2002 to mid-2011

Map 2 below shows the percentage growth between the revised mid-2002 and the mid-2011 Westminster parliamentary constituency estimates for England and Wales.

In total, 541 parliamentary constituencies (94.4%) had a total population increase between mid-2002 and mid-2011. The two parliamentary constituencies with the largest percentage increase were Manchester Central (30.7%) and Poplar and Limehouse (30.2%). Conversely, a total of 32 parliamentary constituencies (5.6%) had a total population decrease between mid-2002 and mid-2011. These population decreases ranged from 0.1% to 4.4%. The parliamentary constituency with the largest percentage decrease was Houghton and Sunderland South with a decrease of 4.4%.

Map 2: Percentage population growth by Westminster parliamentary constituency, mid-2002 to mid-2011, England and Wales

Source: Office for National Statistics

Electoral wards – change over the decade, mid-2002 to mid-2011

Figure 1 shows the percentage growth between the revised mid-2002 and the census based mid-2011 ward estimates for England and Wales. Forty four per cent of wards saw population growth of more than 5% between mid-2002 and mid-2011. Four per cent of wards saw a decline of 5% or more between mid-2002 and mid-2011.

Other small area population estimates for Scotland and Northern Ireland are produced by National Records of Scotland (NRS) and the Northern Ireland Statistics and Research Agency (NISRA) respectively. A paper, Small Area Population Estimates across the UK which provides a broad description of the different methodologies used to produce the wider set of small area population estimates in each constituent country of the UK, is available on the NISRA website.

Population estimates for Scottish NHS Boards, Westminster parliamentary constituencies, and data zones are published by NRS. Further information on these estimates is available on their website.

NISRA publish population estimates for the Health and Social Services Board and the five Health and Social Care Trusts in Northern Ireland, as well as estimates for Westminster parliamentary constituencies and wards. Further information on these estimates is available on their website.

Population estimates for the seven Welsh Local Health Boards, which consist of one or more unitary authorities, are created using a cohort component based method and published on the Welsh Government website.

ONS produce statistics on the size, structure and geographic distribution of the population, on the factors driving population change (births, deaths and migration) and on topics such families and older people. In addition to the main national and local authority mid-year population estimates and the Super Output Area (SOA) estimates, other population estimates are produced; for example, estimates of the very elderly.

In addition, detailed results from the 2011 Census provide information on the characteristics, for example, country of birth or marital status for small areas.

An Overview of Population Statistics is available on the ONS website.