This bulletin presents information from the interim 2011-based subnational population projections for England and provides some guidance on using the data.
These projections update the 2010-based projections published by the Office for National Statistics (ONS) in March 2012 and project the population for 10 years to 2021. They are based on the 2011 mid-year population estimates published on 25 September 2012, which are rolled forward from the 2011 Census. They therefore provide the best estimates of the future population of English regions and local authorities currently available.
They assume a continuation of the estimated trends in fertility, mortality and migration as used in the 2010-based projections and are constrained to the assumptions made for the 2010-based national population projections. The trends from the 2010-based projections have been used because a revised historic data series is not yet available to update the assumptions. The impact on the projections is described in more detail in the User Guidance section of this Statistical Bulletin.
Subnational population projections by age and sex are usually produced every two years. These interim projections are not in the usual schedule of releases but have been produced to meet specific user requirements for an updated set of projections which incorporate data from the 2011 Census but are only required to 2021.
These projections are not forecasts and do not attempt to predict the impact that future government or local policies, changing economic circumstances or other factors might have on demographic behaviour.
The primary purpose of the subnational projections is to provide an estimate of the future size and age structure of the population of local authorities in England. These are used as a common framework for informing local-level policy and planning in a number of different fields as they are produced in a consistent way.
Examples of uses made of population projections include:
The Department for Communities and Local Government (DCLG) when calculating the allocation of central government resources to local areas.
Locally they are used to inform planning of healthcare, education and other service provisions.
Subnational projections also form the basis for other products such as household projections, and by researchers and other organisations that also produce their own projections.
Projections become increasingly uncertain the further they are carried forward due to the inherent uncertainty of demographic behaviour. This is particularly so for smaller geographical areas.
This bulletin provides information on the projected population after five and 10 years. For more information on how ONS population projections meet user needs along with information on their fitness for purpose, the report on quality and methodology (216.3 Kb Pdf) is available on the ONS website.
The interim 2011-based subnational population projections update previously published projections with the latest available population estimates which are based on results from the 2011 Census. This provides an improved population base from which the projections start for all areas. The trends used to produce the 2010-based subnational population projections have then been applied by single year of age and sex to the base population. The resulting projections may therefore be quite different from the 2010-based projections since they are dependent not only on the size of the base population, but also the age and sex structure.
Although the projections start from an improved population base, there are some specific issues which arise from applying the trends from the 2010-based projections, since the assumptions were set using population data before the 2011 Census results were available. These issues are described in more detail below.
The subnational projections are constrained at the national level to a set of England control totals which are based on the 2011 population estimates and the principal assumptions from the 2010-based national population projections. The 2011 population estimates for England are 452,000 higher than the previously published 2010-based projection for 2011. This has an impact on the starting point of the projection, but also when the fertility and mortality rates are applied to the population. Assumed levels of future international migration are not affected.
By 2021, the interim 2011-based projection projects 667,000 more people than the 2010-based projections at the national level (Table 1). This is due to the 452,000 change to the base population, 32,000 extra people due to fewer projected deaths and 184,000 due to additional projected births. The difference between the sets of projections in numbers of projected births and deaths are due to the difference in the underlying size and age structure of the population.
|Mid Year||2011-based projection||2010-based projection||Total change||Change due to:|
|Base population||Projected births||Projected deaths||Projected migrants|
The fertility rates used to set the assumptions are based on birth registrations and population estimates up to 2010. However population estimates for women of childbearing age are likely to have been too low over the decade to mid-2010, as the 2011 Census showed more women aged 16 to 44 than estimates rolled forward from the 2001 Census. This means the fertility rates used to set the assumptions are likely to have been too high, leading to an over-projection of births at the national level.
There are 245,000 more women aged between 16 and 44 in the mid-2011 population estimates for England than in the 2010-based projections for 2011. This results in 184,000 more births being projected over the 10 year projection period than in the 2010-based projections. In the first year of the projection 21,000 more births are projected than in the 2010-based projections, by the 10th year of the projections the difference in the number of births is just over 15,000.
There is a similar issue with the mortality rates since the number of older people, who are most affected by mortality rates, is estimated to be lower in the 2011 mid-year estimates than in the estimates rolled forward from the 2001 Census. The impact is not as great for deaths as it is for births but it also leads to a projected increase in the population.
There are 53,000 fewer people aged 75 and over in the base, who are no longer affected by the mortality rates of that age group. In the first year of the projection 5,600 fewer deaths are projected across all ages than in the 2010-based projections. The effect decreases over the projection period and by the 10th year of the projections the difference in the number of deaths is less than 1,000 a year.
At a subnational level, the impact on local areas in terms of the reduced number of deaths is likely to be small, although areas where 2011 population estimates show fewer people aged 75 and over than in the 2010-based projections may be affected.
However, more areas are affected by the over-projected number of births and caution should be used when interpreting the population aged 0 to 9 in these projections. In particular the projected population aged 0 in mid-2012, the projected population aged 0 to 1 in mid-2013 and so on to those aged 0 to 9 in 2021. Areas most affected will be those where the number of women aged 16 to 44 in the base population is very different to that projected for 2011 in the 2010-based population projections.
Differences in the age structure at local authority level have also resulted in changes to projected levels of internal migration, that is, people moving their area of residence from one local authority to another within England. This is because migration rates based on historic trend data are applied to the new population base. Where the size and structure of the new population base in a local authority is very different from the 2010-based projections for 2011, particularly at ages most likely to migrate, the applied migration rate may over or underestimate the number of people moving from an area.
Adjustments have been made for some areas where it was identified that there were large differences in the population for a number of age groups. These areas are Bournemouth, Cambridge, Malvern Hills, North Dorset, Richmondshire, Rutland, Tunbridge Wells and West Dorset. Adjustments made to the Isles of Scilly, Oadby and Wigston and Rutland in the 2010-based projections have been repeated in the interim 2011-based projections. Detailed information on all the adjustments made is available in the methodology report.
An improvement was also made to the standardisation method used which has resulted in different projected international emigration from the 2010-based projections, although the historic trend data used are the same. There are no changes to the levels of projected international immigration.
Reference tables containing projected populations by males, females and persons, for all years by single year of age, for all local authorities have been published as part of the release. Data have been published unrounded to facilitate onward processing but we recommend that users should use these aggregated to 5 year age groups and rounded.
The interim 2011-based population projections project the population of England to grow by 4.6 million by 2021. This 8.6 per cent growth over 10 years is equivalent to an average annual growth rate of 0.8 per cent. All regions of England are projected to see population growth over the 10 year period to 2021 but the rate of that growth varies. Three regions are projected to grow faster than the national average with London projected to grow the fastest, by 14.2 per cent over the 10 year period. The East is projected to grow by 10.2 per cent, and the South East by 9.3 per cent. The East Midlands is projected to grow at the same rate as England. The region projected to grow at the slowest rate over the next 10 years is the North West at 4.4 per cent (Table 2).
|Population (thousands)||Percentage population change by age group|
|mid-2011||mid-2021||All ages||0-15||16-64||65 and over|
|Yorkshire and The Humber||5,288||5,657||7.0||9.3||2.4||22.2|
Of the 14.2 per cent projected growth in London, 12.4 per cent is due to the difference between births and deaths and just 1.7 per cent to net migration (Table 3). Although London is a popular destination for people moving from other regions and from abroad, there are also large numbers of people who migrate out of London. So despite the large flows of population in and out of the region, the effect of net migration on population growth is projected to be relatively low. London as a region has a relatively young age structure, with little over 11 per cent of its population being aged 65 and over in 2011 compared with most other regions which have about 17 per cent of the population aged 65 and over. Since mortality rates are higher in the older age groups, relatively fewer deaths are projected in London than elsewhere.
|Difference between births & deaths||Migration and other changes||Internal migration||International migration|
|Yorkshire and The Humber||7.0||4.2||2.8||-0.1||2.9|
London also has a correspondingly larger proportion of its population aged 16 to 64. In particular, nearly half the population in 2011 are estimated to be aged between 16 and 44 years old, the main childbearing ages. In most other regions the proportion in this age group is just less than two fifths. This partly drives the higher number of births being projected in London over the next 10 year and the 19 per cent projected increase in the number of children between 2011 and 2021. However, London also shows the over-projection of births caused by applying the fertility rates from the 2010-based projections to the 2011 base (Figure 1) since the estimated number of women aged 16 to 44 in London is 81,000 higher in the 2011 mid-year population estimates than the 2010-based projection for 2011.
These subnational population projections take the 2011 mid-year population estimates which were published on 25 September 2012 as their starting point. The projected local authority population for each year is calculated by ageing on the population for the previous year, applying assumed local fertility and mortality rates to calculate the number of projected births and deaths, and then adjusting for migration into and out of each local authority.
Local authority assumed levels of fertility, mortality and migration are derived from observed values for the years 2005 to 2010 as used in the 2010-based subnational population projections and are constrained to the assumptions made in the 2010-based national projections. Finally, the projections are constrained to a set of England control figures which were produced using the 2011 mid-year estimate for England and the assumptions from the 2010-based national population projections.
As described in the user guidance section of this Statistical Bulletin, there are some issues around the previous assumptions of fertility, mortality and internal migration being applied to the new population base. Adjustments have been made to local authorities most affected by the impact on internal migration.
An improvement was also made to the standardisation method used which has resulted in different projected emigration to the 2010-based projections, although the historic trend data used are the same.
A full description of the methodology used to produce the subnational population projections, including detailed information on the adjustments made to internal migration is available in the interim 2011-based subnational population projections methodology report.
Further information on 2011-based subnational population projections for England is available on the ONS website.
Information on the 2011 population estimates on which these projections are based released on 25 September 2012 are also available on the ONS website.
Information on the 2011 Census is available at the ONS website.
Subnational population projections for the other constituent countries of the UK are produced by the devolved administrations:
The latest 2010-based projections for Scotland.
The latest projections for Wales and Northern Ireland are 2008-based:
The next set of subnational population projections for England have not yet been announced
Office for National Statistics,
South Wales NP10 8XG.
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quality and methodology information report for subnational population projections (216.3 Kb Pdf)
for England is available on the ONS website.
A new set of projections is normally made every second year, however these interim 2011-based projections have been produced in response to user demand to have a set of projections to 2021 which incorporate the 2011 Census results by October 2012.
Full details of the interim 2011-based subnational population projections for England are available on the ONS website.
Details of the 2010-based subnational population projections published in March 2012 are available on the ONS website.
Subnational population projections are produced on a consistent basis across all local authorities in England. The interim 2011-based subnational population projections for England are fully consistent with the 2011 mid-year population estimates published on 25 September 2012.
Reference tables containing projections for males, females and persons, for all years by single year of age, for all administrative areas are produced and published as part of the release. Data have been published unrounded to facilitate onward processing but users are advised that they should use these aggregated to 5 year age groups and rounded.
Projections are made of the usually resident population, as defined for the mid-year population estimates. The population includes all usually resident persons, whatever their nationality. Members of HM Armed Forces in England are included, but members of HM Armed Forces and their families who are abroad are excluded. Members of foreign armed forces in England are also included, as are any accompanying dependants.
Assumptions made about future fertility, mortality and migration at local authority level in the interim 2011-based subnational population projections are the same as those used to produce the 2010-based projections. These are based upon recent observed trends from the components of change as published with the indicative 2010 mid-year population estimates on 17 November 2011.The assumptions do not take account of future policy changes nor local development policies that have not yet occurred. Further information on the methodology is available on the ONS website.
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