Population estimates by output areas, electoral, health and other geographies, England and Wales: mid-2020

• In the year to mid-2020 the population of England and Wales continued to grow with the population in areas described as Cosmopolitan student neighbourhoods experiencing the highest increase at 1.8%.

• Areas classified as Countryside living and Suburban living continue to have the lowest proportions of those aged 16 to 64 years, and the highest proportions of those aged 65 years and over.

• The population estimates in this release are consistent with the Mid-year population estimates published on 25 June 2021.

Super Output Areas (SOAs) are statistical geographies designed to improve the reporting of Small Area statistics. They are built from groups of census Output Areas, are of a consistent population size, and are not subject to boundary changes between censuses.

One way of understanding how the population varies across England and Wales is to use the 2011 Lower layer Super Output Area (LSOA) area classification; this classifies each LSOA in England and Wales according to its demographic characteristics based on the 2011 Census. Table 1 gives a summary of the population for each area type.

The population of LSOAs classified as Cosmopolitan student neighbourhoods is estimated to have increased by 1.8% between mid-2019 and mid-2020, while across England and Wales as a whole, the population grew by 0.5%. This partly reflects that much of the year was not impacted by the coronavirus (COVID-19) pandemic. Students went to university in autumn 2019 and levels of international migration were relatively high. However, many moves out of these areas, which would have occurred in the spring and summer of 2020, were either postponed or were not accompanied by updates to the administrative data underpinning these statistics. You can find further information on this, focussing on local authority level, in the mid-year estimates release.

Table 1 shows that areas classified as Countryside living and Suburban living had the largest proportions of people aged 65 years and over (26.7% and 25.3% respectively) as well as the highest median ages (50.3 and 48.3 years respectively).

Conversely, areas classified as Cosmopolitan student neighbourhoods and Inner-city cosmopolitan had the largest proportions of people aged 16 to 64 years (81.7% and 71.6% respectively).

LSOAs classified as Multicultural living had the highest proportion of people aged 0 to 15 years (24.3%) while Cosmopolitan student neighbourhoods had the lowest (9.9%).

On average LSOAs classified as Countryside living had a lower population density than England and Wales as a whole (63 and 395 people per square kilometre (sq km) respectively). For other types of area, population densities ranged from around 1,000 people per sq km (Suburban living and Industrious communities) to nearly 11,000 people per sq km (Inner city cosmopolitan).

The local authority population estimates for mid-2021, rolled forward from Census 2021, are planned for release in September 2022. These will be followed by population estimates for Census 2021-based Super Output Areas (SOAs) at a later date.

Beyond this it is our ambition to deliver a fully-transformed population and migration system by 2023, making regular improvements to our statistics along the way as more administrative data become available. For more information on our future plans for improving population statistics, please see population and migration statistics system transformation – recent updates.

The Office for Statistics Regulation (OSR) published a review of population estimates and projections in May 2021. Many of the issues outlined are also relevant to this release. The review identified the need to keep methods current and responsive at lower levels where there is more variability in the data. We published a detailed response to the OSR review in July 2021, which contains an outline of our plans to address these issues. We will make clear when we publish research that addresses the issues raised by the OSR review, and how it fits into the wider transformation of population statistics.

Population estimates

Population estimates provide statistics on the current size and age structure of the population in the UK at country, region, county, and local authority level. They are the official source of estimated population size in between censuses and inform a wide range of National Statistics.

Mid-year

Mid-year refers to 30 June of any given year.

Usually resident population

These data estimate the “usually resident population”. This is the standard UN definition and includes only people who reside in a country for 12 months or more, making them usually resident in that country. As such, visitors and short-term migrants are excluded.

Median age

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).

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 layer Super Output Areas (LSOAs) by broad ages and Middle layer Super Output Areas (MSOAs) by quinary age groups (five-year age groups) hold National Statistics status. Estimates at greater levels of disaggregation, for example by single year of age, are provided as 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. First, 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.

This bulletin has described estimates for LSOAs. This data, along with estimates for output areas and geography lookups from the Office for National Statistics (ONS) Open Geography Portal enable additional geographic breakdowns to be produced.

Nomis

Population estimates for mid-2011 to mid-2020 are also available through Nomis. Nomis holds additional geographic breakdowns not published on the ONS website such as major towns and cities, built-up areas, Travel to Work areas (2011) and some data on historic ward boundaries.

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 (QMI) report has further information on the quality and use of these statistics.

The mid-2020 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 GP Patient Register data in 2020 has increased or decreased in a large number of Lower layer Super Output Areas (LSOAs) and Middle layer Super Output Areas (MSOAs) compared with 2019 data, which may be because of 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. It is likely that the coronavirus (COVID-19) pandemic has had an impact on the data used in this release.

All population estimates are subject to statistical uncertainty and this is generally highest for estimates of Small Areas, areas with high levels of population churn, and at the end of the inter-census period.