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1. Background and Methodology, 2012-based National Population Projections This product is designated as National Statistics

Released: 06 November 2013 Download PDF

Introduction

National population projections by age and sex are produced for the UK and constituent countries every two years. These sets of projections are based on a review of the underlying assumptions regarding fertility, mortality and migration.

The primary purpose of the projections is to provide an estimate of future population which is used as a common framework for national planning in a number of different fields. The main focus of the 2012-based projections is on the next 25 years up to mid-2037, though longer term projections to mid-2112 are also produced. Population projections become increasingly uncertain the further they are carried forward and particularly so for smaller geographical areas and age-sex breakdowns. In addition to the principal (main) projections, variant projections are also available, based on alternative assumptions of future fertility, mortality and migration. For more information on how ONS projections meet users’ needs along with information on their fitness for purpose, please see the report on quality and methodology (109.5 Kb Pdf) on the ONS website.

The 2012-based projections replace the 2010-based projections published on 26 October 2011.

The projections were produced by ONS on behalf of the National Statistician and the Registrars General of Scotland and Northern Ireland. The underlying assumptions were agreed in liaison with the devolved administrations – Welsh Government, National Records of Scotland (NRS) and Northern Ireland Statistics and Research Agency (NISRA) - following consultation with key users of projections in each country and advice from an expert academic advisory panel.

ONS has been responsible for the production of the official national population projections for the UK and its constituent countries since 31 January 2006. Prior to this, the responsibility lay with the Government Actuary’s Department (GAD).

This report contains background information for the 2012-based national population projections. Included are sections on:

  • defining the base population,

  • the method of projections,

  • the projection period,

  • background on principal and variant projections,

  • the relationship of UK level projections to individual country level projections,

  • summary of the long-term assumptions of future levels of fertility, mortality and migration,

  • changes to the State Pension age,

  • national population projections expert advisory panel.

Base Population

Definition

The projections are based on estimates of the resident population of the UK and its constituent countries at mid-2012. The population includes all usually resident persons, whatever their nationality. Members of HM Armed Forces in the UK are included, but members of HM Armed Forces and their families who are abroad are excluded. Members of foreign armed forces in the UK are included, with any accompanying dependants.

Base populations for individual countries

The projections for England and Wales are based on the mid-2012 population estimates published by ONS on 26 June 2013. The projections for Scotland are based on the mid-2012 population estimates published by NRS on 8 August 2013, and likewise the projections for Northern Ireland are based on the mid-2012 estimates published by NISRA on 26 June 2013. These estimates are based on the results from the 2011 Census.

Table 1-1: Base population estimates for 2012-based projections

Thousands
   
England 53,494
Wales 3,074
Scotland 5,314
Northern Ireland 1,824
United Kingdom 63,705

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Estimates of the population aged 90 and over

Official mid-year population estimates produced by ONS, NRS and NISRA are prepared by individual age to the age of 89, with an upper age band for all those aged 90 and over. Estimates of the population aged 90 to 104 by single year of age and for the 105 and over age group are prepared using the Kannisto Thatcher survivor ratio method, with the results controlled to agree with the official estimates of all those aged 90 and over.

Method of Projection

The projections are made for successive years running from one mid-year to the next. For each age the starting population, taking into account net migration less the number of deaths, produces the number in the population, one year older, at the end of the year.  To this has to be added survivors of those born during the year.  Age is defined as completed years at the last birthday.

Migration is assumed to occur evenly throughout the year. For computing purposes, this is equivalent to assuming that half the migrants in a given year at a given age migrate at the beginning of the year and half at the end of the year. The number of net migrants to be added to obtain the population aged x+1 at the end of the projection year therefore consists of half of those migrating during the year at age x and half of those migrating during the year at age x+1.

The number of deaths in a year is obtained by adding half of the net inward migrants at each age to the number in the population at the beginning of the year and applying the mortality rate qx. The mortality rates used in the projections represent the probabilities of death between one mid-year and the next, according to a person's age last birthday at the beginning of the period. The appropriate rate of ‘infant mortality’, that is, the probability of a new-born child not surviving until the following mid-year is also given. This is about 85 per cent of the full, first year of life infant mortality rate used in official statistics.

The number of births in the year is calculated by multiplying the average number of women at each single year of age during the year (taken as the mean of the populations at that age at the beginning and end of the year) by the fertility rate applicable to them during that year.  The total number of births in a year is assumed to be divided between the sexes in the ratio of 105 males to 100 females, in line with recent experience. The number of infants aged 0 at the end of the year is calculated by taking the projected number of births, deducting the number of deaths found by applying the infant mortality rate and adding half the number of net migrants aged 0 last birthday.

The principal projections are computed for each of the constituent countries of the UK and the results are added together to produce projections for England & Wales, Great Britain and the UK.

The assumptions have mostly been set using rates based on revised series of population estimates and thus take into account the results of the 2011 Census. The exceptions to this are the mortality and fertility assumptions for Scotland. A revised back series of population estimates for Scotland was not available in time so data rolled forward from the 2001 Census were used. Differences between the rolled forward estimates and the Census results did not raise any significant concerns about this approach.

Projection Period

For the 2012-based projections, data have been published up to 100 years ahead. However, the long-term figures should be treated with great caution. Population projections become increasingly uncertain the further they are carried forward, and particularly so for smaller geographic areas and age-sex breakdowns.

To emphasise this uncertainty, a distinction is made between four different time periods:

  • For each year to mid-2037 (the first 25 years of the projection period), the projected population is published for both five year age groups and by single year of age.

  • For selected years from mid-2037 to mid-2062 (from 25 to 50 years ahead), the projected population is also published for both five year age groups and by single year of age.

  • For selected years from mid-2062 to mid-2087 (from 50 to 75 years ahead), the projected population is published for five year age groups only.

  • For selected years from mid-2087 to mid-2112 (from 75 to 100 years ahead) the projected population is published for five year age groups only. These results are not considered appropriate for a wide range of uses but have been made available in line with making datasets publicly available under the government’s transparency agenda.

Projections by single year of age and sex for all years up to mid-2112 are available in the zipped population projections data files found in the data section of this publication. These datasets are published as part of the government’s open data agenda and their use will be mainly for modelling purposes. Users should note the metadata provided in the files before using these datasets.

Principal and Variant Projections

Background

The principal population projections provide a consistent starting point for all government planning which is affected by the numbers in the population. They are based on assumptions considered to be the best that could be made at the time they are adopted. However, due to the inherent uncertainty of demographic behaviour, any set of projections will inevitably be proved wrong, to a greater or lesser extent, as a forecast of future demographic events or population structure. To give users of the projections an indication of this uncertainty and to explore alternative scenarios, a number of variant population projections have also been produced, based on alternative assumptions of future fertility, mortality and migration.

Variants available from the 2012-based projections

In addition to the principal assumptions, high and low variant assumptions have been prepared for each of the three components of demographic change - fertility, life expectancy and migration. These variant assumptions are intended as plausible alternatives to the principal assumptions and do not represent upper or lower limits for future demographic behaviour.

Aside from the principal projection, nine standard variant projections are presented here. These are the six possible ‘single component’ variants (that is, varying only one component at a time from the principal assumptions); and two ‘combination’ variants: those produce the largest/smallest total population size, and one special case scenario of zero net migration (also known as natural change only). Seven further variant projections will be released on 10 December 2013, see tables 1.2 and 1.3.

The variants allow users to explore a range of different possible future demographic situations. For example, the high and low migration variants for the UK provide alternative plausible scenarios for long term net international migration at 60,000 above and below the principal net migration assumption, respectively. The low variant therefore assumes net migration of 105,000 per year, while the high variant assumes net migration of 225,000 per year.

In addition to high and low variants for the fertility, mortality and migration assumptions, other scenarios include ‘no change’, which assumes that fertility and mortality rates will remain constant at current levels, and ‘zero net migration’, which allows the effects of the projected trends in fertility and mortality to be examined independently of the effects of migration.

List of available variants

The 2012-based variant population projections are based on the categories of assumptions shown in Table 1-2.

Table 1-2: Assumptions for the three components of demographic change

    Fertility  Life expectancy Net migration
 Standard variants 
i  High  High  High
ii  Principal  Principal  Principal
iii  Low  Low  Low
 Special case scenarios 
iv  Replacement1  No improvement1  Zero
v  Constant1    Long-term balanced (UK only)1

Table notes:

  1. Due to be published on 10th December 2013.

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From these categories of assumptions, the variant projections released on 6 November 2013 have been created as shown in Table 1-3.

Table 1-3: Variant projections

Fertility  Life expectancy  Net migration
         
A  Principal projection  Principal  Principal  Principal
 
 Standard ‘single component’ variants 
B  High fertility  High  Principal  Principal
C  Low fertility  Low  Principal  Principal
D  High life expectancy  Principal  High  Principal
E  Low life expectancy  Principal  Low  Principal
F  High migration  Principal  Principal  High
G  Low migration  Principal  Principal  Low
 
 Standard ‘combination’ variants 
H  High population  High  High  High
I  Low population  Low  Low  Low
K  Young age structure1  High  Low  High
L  Old age structure1  Low  High  Low
 
 Special case scenarios 
O  Replacement fertility1  Replacement  Principal  Principal
P  Constant fertility1  Constant  Principal  Principal
Q  No mortality improvement1  Principal  No improvement  Principal
J  Zero net migration (natural change only)  Principal  Principal  Zero
R  No change1  Constant  No improvement  Principal
U  Long-term balanced net migration (UK only)1  Principal  Principal  Long-term balanced

Table notes:

  1. Due to be published on 10th December 2013.

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Relationship of UK level projections to individual country level projections

Principal projections

In the principal projections, the UK projection is calculated simply as the sum of the projections for the four individual countries (England, Wales, Scotland and Northern Ireland). Therefore, the projected population numbers, deaths at each age, and births at each age of mother for the UK are just the sum of those for the four individual countries. The 'assumed' UK fertility and mortality rates are then 'back-calculated' from these projected births, deaths and population numbers.

Standard variants

However, it does not necessarily follow that the same process should be used for variant projections. It is intended that the standard variants for individual countries should represent broadly comparable margins of uncertainty to those for the UK. However, for migration at least, relative uncertainty tends to increase for smaller areas. In particular, for Scotland, Wales and Northern Ireland, migration flows from the rest of the UK are at least as large as international migration flows from outside the UK. These cross-border flows, therefore, account for much of the uncertainty regarding total net migration for these countries. However cross-border migration flows cannot be high in all four countries simultaneously, or low for all countries, as they must sum to zero at UK level.

For these reasons the variant migration assumptions for the UK are 'non-additive', that is, they have not been calculated as the sum of those for the four individual countries. For fertility and mortality, however, uncertainty at UK and individual country level is unlikely to differ significantly. The variant fertility assumptions and the variant mortality assumptions for the UK have been calculated directly from those for the individual countries by the same back-calculation process used for the principal projections.

Summary of Long-term Assumptions

The new principal projections are based on the long-term assumptions of future fertility, mortality and net migration (that is, immigrants less emigrants) and are summarised in Table 1-4. These have been agreed in consultation with NISRA, NRS and the Welsh Government. Comparisons are given with the assumptions made for the previous 2010-based projections. It should be noted that the fertility and mortality assumptions for Scotland are based on data rolled forward from the 2001 Census because the revised back series based on the 2011 Census was unavailable when the assumptions were set.

Table 1-4: Long-term assumptions for the 2012-based national population projections compared with assumptions for the 2010-based projections

United Kingdom England Wales Scotland Northern Ireland
Fertility – Long-term average number of children per woman  
2012-based   1.89 1.90 1.90 1.75 2.00
2010-based   1.84 1.85 1.85 1.70 1.95
 
Mortality - Expectation of life at birth in 2037*  
Males 2012-based   84.0 84.3 83.6 81.9 83.3
Males 2010-based   83.6 83.9 83.1 81.1 82.6
Females 2012-based   87.3 87.5 86.9 85.4 86.8
Females 2010-based   87.2 87.4 86.8 85.4 86.8
 
Net migration – Annual long-term assumption  
2012-based   +165,000 +143,500 +6,000 +15,500 0
2010-based   +200,000 +172,500 +10,000 +17,500 0
             

Table notes:

  1. * Expectations of life for 25 years ahead given as specimen year. Note these are period expectations of life based on the mid-year mortality  rates assumed for the year 2037 and do not take account of the continuing improvement in mortality projected beyond 2037. 
  2. † Net migration includes international migration and cross-border migration between the countries of the UK.

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For the UK, the long-term assumption of average family size is 1.89 children per woman, an increase of 0.05 compared with the 2010-based projections. The long-term UK fertility assumption in official national projections has been lowered on a number of occasions since the 1960s baby boom, but it has been increased for the 2012-based projections, reflecting the overall increasing fertility rates seen in all four countries of the UK over the past decade. More information can be found in the fertility assumptions section of the release.

The 2012-based projections match the 2010-based projections in terms of improvements in mortality. The assumed rates of mortality improvement in the ‘target’ year 2037 (the target year is the 25th year of the projection period) is 1.2 per cent per year for both males and females, for those born in 1939 and later.  For those born before 1939 the improvement rate is assumed to increase to a peak of 2.5 per cent for those born in 1931 and 1932 declining back to 1.0 per cent for those born in 1922 and earlier.  These are the same assumptions for the rates of mortality improvement in the target year as those used in the 2010-based projections (where the target year was 2035).

Projected period life expectancies at birth for the year 2037 are around 0.4 to 0.8 years higher than in the previous projections for males and broadly similar for females. Female rates of mortality improvement are assumed to converge to the proposed target rates in 2037 at the same speed as for males whereas, in the 2010-based projections, female rates were assumed to converge at a slower rate. More information can be found in the mortality assumptions section of the release.

The new long-term assumption for net migration to the UK is +165,000 each year compared with +200,000 a year in the 2010-based projections. This decrease is due to taking account of final migration data for two new years (2011 and 2012), which have shown a fall in net migration compared with 2010. More information can be found in the migration assumptions section of the release.

National Population Projections Advisory Panel

An expert academic panel advises ONS early on in the assumptions setting process on current and emerging demographic trends and their possible implications for the national population projections. This panel met in 2013 to advise on the assumptions for 2012-based population projections.
 
The membership of the panel is as follows:

Panel meeting

A note of the panel meeting held on 19 April 2013 is available in appendix A.

Questionnaire

The panel completed a questionnaire where they were asked what they thought were the most likely future levels of fertility, life expectancy and migration. They were also asked for their views on the validity and importance of a wide range of arguments which might be thought likely to influence future trends. The questionnaire was devised by the International Institute for Applied Systems Analysis (IIASA) in Vienna and was adapted by ONS for use in the UK. It is reviewed for each projection round to ensure that the experts’ views on current and emerging trends are collected.

Due to the changes to the migration assumptions setting methodology, the questionnaire for this round of projections had a focus on migration assumptions and trends.

Details of the panel’s views on the most likely levels of the total fertility rate, life expectancy at birth and total net migration to the UK (and associated 67 per cent and 95 per cent confidence intervals) in the years 2016 and 2036 can be found in appendix B.

Changing State Pension Age

Pensionable ages for men and women

Full details about the current and planned changes to State Pension ages under the Pensions Acts of 1995, 2007 and 2011 can be found in appendix C.

Between 2010 and 2020, State Pension age will change from 65 years for men and 60 years for women, to 66 years for both sexes.

  • Any woman born before 6 April 1950 will attain pensionable age when she reaches the age of 60.

  • For women born between 6 April 1950 and 5 December 1953, the date that pensionable age will be attained can be found in appendix C, table 1-5.

  • For men and women born between 6 December 1953 and 5 October 1954, the date that pensionable age will be attained can be found in appendix C, table 1-6.

State Pension age will then increase progressively from 66 years to 68 years for both men and women between 2034 and 2046.

  • Any person born after 5 October 1954 but before 6 April 1968 will attain pensionable age when he or she reaches the age of 66.

  • For persons born between 6 April 1968 and 5 April 1969, the date that pensionable age is attained is shown in appendix C, table 1-7.

  • Any person born after 5 April 1969 but before 6 April 1977 will attain pension age when he or she reaches the age of 67.

  • For persons born between 6 April 1977 and 5 April 1978, the date that pensionable age will be attained can be found in appendix C, table 1-8.

  • Any person born after 5 April 1978 will attain pensionable age when he or she attains the age of 68.

Sources: Pensions Act 1995 Chapter 26 Part II Section 126 and Schedule 4; Pensions Act 2007 Chapter 22 Part I Section 13 and Schedule 3; Pensions Act 2011 Part 1 Section 1 and Schedule 1.

The data presented in this bulletin do not reflect proposed further changes to the State Pension age published by the government. They propose bringing forward the increase in State Pension age to 67, to be phased in between 2026 and 2028.   These proposed changes are not yet law and still require the approval of Parliament.  Further information relating to these proposals can be found at the Gov.uk website.

Calculation of populations of working age and pensionable age for national population projections

  • From 2004 to 2009, all women aged 60 to 64 are of pensionable age. From 2021 to 2033, all women aged 60 to 65 are of working age. From 2010 to 2020, the number of women aged 60 to 65 who are of pensionable age is calculated using table 1-9 in appendix C.

  • Similarly, from 2021 to 2033, all persons aged 66 and over are of pensionable age. From 2036 to 2043, all persons aged 66 are of working age and all persons aged 67 and over are of pensionable age. From 2034 to 2035, the number of men and women aged 66 who are of pensionable age is calculated using table 1-10 in appendix C.

  • From 2046 onwards, all persons aged 68 and over are of pensionable age and all persons aged 67 are of working age. From 2044 to 2045, the number of men and women aged 67 who are of pensionable age is calculated using table 1-10 in appendix C.

Background notes

  1. Details of the policy governing the release of new data are available by visiting www.statisticsauthority.gov.uk/assessment/code-of-practice/index.html or from the Media Relations Office email: media.relations@ons.gsi.gov.uk

    These National Statistics are produced to high professional standards and released according to the arrangements approved by the UK Statistics Authority.

Appendix A: Note of the Meeting of the National Population Projections Expert Advisory Group

NPP Expert Advisory Panel Meeting

Notes of meeting held on 19 April 2013.

Location: Room LG1, Government Actuary's Department, Finlaison House, 15-17 Furnival Street, London EC4A 1AB.

Expert group 

Dr Ann Berrington, University of Southampton
Dr Scott Blinder, University of Oxford
Prof. Emily Grundy, University of Cambridge
Prof. Les Mayhew, City University
Prof. John Salt, University College, London
Dr Chris Wilson, University of St Andrews

ONS Population Statistics Division attendees

Oliver Dormon, Demographic Analysis Unit
Suzie Dunsmith, Population Projections Unit
Adrian Gallop, Demographic Analysis Unit and Government Actuary’s Department
Ben Humberstone, Deputy Director Population Statistics Division (Chair)
Julie Mills, Demographic Analysis Unit

Observers

Esta Clark, National Records of Scotland (audio link)
Julie Jefferies, ONS
Fern Leather, ONS
Ronan O’Kelly, National Records of Scotland
Louise O’Leary, ONS
Tony Whiffen, Welsh Government
Jo Zumpe, ONS (audio link)

Apologies

Prof. Carol Jagger, Newcastle University

1. Introduction

1.1 Ben Humberstone (BH) welcomed everyone on behalf of ONS and gave a brief introduction. 
The main aim of this meeting was to have an informed discussion about the long-term assumptions for the forthcoming UK-level population projections.

1.2 The role of the expert panel is strictly advisory. It was emphasised that ONS was not seeking a consensus where none exists and wanted to hear the full range of views on the key assumptions. Though all opinions would be considered, the final decision on the assumptions to be adopted for the next set of projections rests with ONS and the Registrars General.

1.3 The 2012-based population projections are scheduled for publication in Autumn 2013.

1.4 ONS would give introductory presentations on each of the three sets of assumptions – fertility, mortality and migration, after which the floor would be opened up for general discussion. A questionnaire on the assumptions had been sent to all of the experts.

2. Fertility

Introduction

2.1 Oliver Dormon’s (OD) presentation began by reviewing the recent trends in period and cohort fertility including a comparison of the actual unrevised 2010-based UK Total Fertility Rate (TFR) as used in the last projection round and the rebased time series from 2002-2010 using the Census denominator.

2.2 It was noted that the UK rebased TFR for 2010 was 1.93, compared with 1.97 in the last projection round. Based on the births for the first three quarters, the TFR for 2012 was not expected to be significantly different meaning that, overall, the TFR had remained fairly stable for the past four years. The rebased TFR for the UK remained provisional as it included revised population figures for England and Wales but not yet for Scotland and Northern Ireland, although this was unlikely to make a large difference.

2.3  The experts agreed that this rebasing would likely have an impact, but it was felt that fertility in 2016 was likely to be similar to the last four years (which have shown little change), in the absence of any compelling evidence to the contrary. In essence, the experts felt that the 2010 round expert estimate was too low, rather than the 2012 expert estimate being too high. It was also acknowledged that the experts made their predictions before fully assimilating the impact of the rebasing. A comment was made that the rebased TFR was a better denominator and this should be used for comparison going forward.

2.4 OD noted that the trends in the countries of the UK have remained broadly stable, with England and Wales at a similar level as each other, Northern Ireland slightly higher, and Scotland lower.

2.5 OD covered the factors that might have an impact on the level of fertility and noted that there was disagreement between the experts on the effects trends in patterns of education, work and income trends would have on fertility, although all thought they would have an impact.

2.6  OD stated that results from the expert questionnaire suggested that there was evidence that the long-term TFR could be raised from 1.84. He proposed that the discussion should cover this possibility.

Discussion

2. 7 The experts noted that the welfare state may influence UK trends in relation to other countries and OD presented the slide comparing the UK with other European countries, demonstrating that the UK has shown similar fertility trends to Sweden in the last 10 years.

2.8 The panel suggested that it was important to differentiate between enrolment in further education and educational attainment. The high levels of educational enrolment in the late 1980s/early 1990s had the effect of postponement for women in these cohorts. Educational attainment on the other hand influences human capital.

2.9 It was suggested that financial factors could play a role in depressing fertility. For example, paying back student loans, house-buying and the high cost of renting could result in women delaying their fertility.

2.10 The experts suggested that competing factors such as political changes (benefit changes, removing family friendly policies) could cancel out the increases to fertility that rising levels of migrant populations with high fertility rates would have. OD then presented some charts which demonstrated that the non-UK born TFR has been consistently higher than the UK born TFR in recent years but that in the latest data, where the UK born TFR has risen slightly, the non-UK born has fallen.

2.11 It was noted that the TFR for Polish migrants was very low – possibly similarly low to the actual Polish TFR, therefore it might be expected that the non-UK born TFR would drop further if the Polish proportion of the ‘stock’ of migrants of childbearing age continued to grow.

2.12 The experts talked about migration in different countries and how large numbers of immigrants brought in to care for the elderly might affect fertility. It was discussed how migrants from China or Poland could have a depressing effect on fertility and noted that, in fact, sub-Saharan Africa was one of the few areas of the world left with high levels of fertility.

2.13 The experts stated that there was no clear evidence that the new policies introduced by the government have had any effect. In fact, the TFR has remained quite stable through the last four years, through a change in government, so empirically there is no clear period evidence to change the assumption from last time.

2.14 One expert queried the questionnaire and suggested that the information provided there and the figure for replacement level fertility have an ‘anchoring’ effect for the experts, so that their judgments would all be within certain limits.

2.15 BH commented that projecting the TFR was not an exact science. Projections were used to estimate school places but there is a great deal of uncertainty around the projections and a broad range of plausible outcomes suggested by the variants. The experts suggested that the level of uncertainty is likely to be underestimated.

2.16 The panel suggested that there is a big difference between looking at the short-term five year projection and the longer term 25 years ahead, particularly when the fluctuation in period fertility can be a year on year change. If the past five years were used to project they would show a period of relative stability, if 10 years were used that shows a considerable increase (since 2001). However, the rebasing has tempered this increase slightly. Again it was underlined how important the rebasing due to the Census was.

2.17 The experts remarked on the findings of a study into the effect of recession on childbearing and the difference between women of different education groups. Women of low educational attainment tended to accelerate their childbearing during times of recession, whereas women of higher attainment tended to postpone.

2.18 It was suggested that a reduction in the availability of grandparent support might have a downward impact on fertility. OD suggested that increases to retirement age might shorten supply of this care. It was thought there was no clear evidence of this at the moment, but there may be in future. The experts noted that in a recent report, this year was the first that more women aged 60 were in work than were not.

2.19 One expert proposed that there were so many competing factors at work that it was difficult to see how they could be weighted on importance and relevance. Some areas had been fully researched, some had not. What resulted was a series of factors that might play a role but the methods by which they were selected, weighted and used to forecast the future TFR were unclear. It was questioned whether they should be used at all.

2.20 The experts noted that a recent study by Myrskylä et al. (2013)1 had produced projections of cohort fertility using five year trends and projecting five years forward. The confidence intervals were large and some experts therefore gave warnings over the use of stochastic forecasting as an alternative to the current method, although this view was not shared by the whole panel. It was also suggested by some that there may be issues with using probabilistic forecasting and the reliance on the recent trends alone in isolation without some level of objectivity.

2.21 The panel noted that the decline in teenage fertility could continue and this could offset the increases in fertility at older ages. However, recent changes to the teenage pregnancy strategy, for example the reduction in the number of teenage pregnancy coordinators, might see a reversal of this trend. Some suggest that the good strategies have set in motion a behavioural shift that will continue the downward trend, even without the support.

2.22 OD asked whether there was any compelling reason why the differentials at UK country level should not remain. It was suggested that there may be a North/South divide forming in terms of fertility trends and that perhaps Northern England was more similar to Scotland in various characteristics including lower levels of fertility, than it was to South East England.

2.23 One expert wondered about the macro changes affecting fertility that would support an increase in TFR. Recent cohorts have stopped postponing in the same way as earlier cohorts had done. Gender equity in the form of more flexible maternal and paternal leave, family friendly policies as well as government rhetoric to protect ‘hard working families’ should serve to prevent a downturn in fertility.

2.24 The panel suggested that global warming, climate change and ecological migration should be considered in estimating the long-term TFR. It was suggested there was evidence that migrants move to a neighbouring country or to one with a common language.  English speaking migrants from Australia, USA and UK had virtually indistinguishable levels of fertility, so movement between these countries would not impact the UK fertility rate.

2.25 The panel stated that most couples’ ideal was still two children. However it was pointed out that although most people report they want two children, even across countries of Europe, clearly this was not borne out in reality. Countries such as Italy were having much lower numbers i.e. 1.4. It was also suggested that low fertility in countries such as Germany was due to longer periods of time spent in further education for some women (up to their late twenties in some cases).

2.26 OD then proposed a flat trajectory. He suggested that there was no strong evidence to support a divergence of UK countries from each other. He asked whether there was evidence for a slightly higher TFR in the long-term and if there was agreement that it would not be any lower than 1.84.

2.27 The experts agreed but queried whether fertility may fall in the short term. It was noted that the conditions for young people in terms of constraints such as job insecurity/uncertainty may well result in a downturn in the short-term but it was unclear whether this would continue. There was broad agreement that fertility would continue to increase for women in their 30s and aged over 40.

2.28 BH noted that the interest around the last set of national projections focused on the 70 million threshold and the experts commented that increasing the TFR to 1.91 for the long-term would have a significant impact on population figures. 

2.29 The approach taken by ONS to consult widely on the projections and the transparency of methods used was praised, stating that this was not always the case across other statistical organisations elsewhere.

1 Myrskylä et al. (2013) New Cohort Fertility Forecasts for the Developed World: Rises, Falls, and Reversals. Population and Development Review 39.1: 31-56.

3. Migration

Introduction

3.1 Suzanne Dunsmith’s (SD) presentation began with a brief description of the new methodology for setting the migration assumptions, which will involve the use of ARIMA time series modelling of gross flows and smoothing the age distributions with the Wilson variant of the Rogers curve.

3.2 The 2010-based assumptions were addressed and it was noted that the long term principal assumption was a net inflow of 200,000 migrants per year, with the high and low variants being +/- 60,000. In 2011, the actual net migration figure was 247,000, which was close to the high variant and, in 2012, it was 163,000, which was closest to the low variant.

3.3 SD noted that long term international migration was steady until the 1990s, after which it started to rise, reaching a peak of 260,000 in 2004-2005. The most recent provisional data however show a significant drop to 163,000 in 2012 from 247,000 in 2011. The latest drop in net migration is mainly due to changes in immigration.

3.4 SD described who was migrating to the UK and noted that over 50 per cent of immigrants are from outside the EU.

3.5 The reasons for migration were then described and it was stated that work and study are the predominant reasons for immigration. It was observed that study has overtaken work as the main reason for migration but there has recently been a drop in immigration for study.

3.6 SD then discussed where people are immigrating from and explained that India, China, Pakistan, Poland and Australia are the five most common countries of origin. She noted that immigration from Poland has levelled off recently from the highs it achieved after EU accession and that China is now the second most popular country of origin, with most Chinese immigrants coming to the UK for study.

3.7 The presentation moved onto emigration and SD noted that 40 per cent of emigrants are British, about a third are from the EU, and the rest are non-EU citizens. The main reason for emigration is work and the most popular destination is Australia, which has been the case since 1996.

3.8 SD then reported on the preliminary analysis of the questionnaire responses. She noted that most experts said that the main motives or pressures from the country of origin would have no or a slight upward effect on migration, and that the attractiveness of the UK and cost of migration would have no or a slight downward effect. The experts generally agreed that migration controls would have a downward effect. The other forces identified by the experts were conflict, instability, environmental change, economy, and labour market policies.

3.9 The central estimate for long term immigration was 623,000 with an upper bound of 933,000 and a lower bound of 392,000 (95 per cent confidence interval). The long term emigration central estimate was 397,000, with an upper bound of 428,000 and a lower bound of 308,000 (95 per cent confidence interval).  The long term net central estimate was 162,000 which was the same as the estimate given by the experts at the 2010-based NPP expert advisory panel.
The central estimates for short term in, out and net migration were 578,000, 334,000 and 183,000 respectively, which therefore suggests a drop-off in migration in the long term.

3.10 SD discussed some of the responses to the questions on forces. Four experts thought that the economy would have an upward effect on immigration with two saying it would have a downward effect and one saying no change. Most experts thought the economy would have an upward effect on emigration. The opinions on the effects of the economy on net migration were mixed, with two experts saying it would have a downward effect, two an upward effect, and two that there would be no change.
Regarding the EU expansion, four experts thought that it would have an upward effect on net migration, two that it would have a downward effect and one that there would be no change. There were mixed views on non-EU migration, suggesting that there is a lot of uncertainty in this area.

3.11 SD then summarised the questions for the panel to discuss:

  • What differences might there be in net migration from EU and non-EU countries?

  • How might current government policies aimed at reducing net migration affect migration? How long might these effects remain?

  • What do you think the impact of the economy will be on migration over the next five years?

  • Will asylum claims increase/decrease? By how much? For how long?

3.12 It was explained that discussion was sought on asylum because a couple of experts had suggested that asylum seeker numbers, which have been constant recently, would increase due to instability in the Middle East, but that one thought that they would decrease and immigrants from China and other emerging economies would increase.

Discussion

3.13 BH asked the panel for their thoughts on whether it is easier to set ins and outs than nets, SD added that ONS would appreciate the panel’s thoughts on the proposed eventual move to using rates, which would lead to variable volumes of migrants throughout the projection horizon. The panel strongly supported the modelling of ins and outs rather than net migration and welcomed the movement to migration rates but did not see this aspect as quite as important as the change to modelling gross flows.

3.14 The panel noted that the 1980s saw a marked shift from emigration to immigration in the UK presumably due to changes in the characteristics of the sending and receiving countries. It was suggested that an economic-based analysis of migration flows would be useful to shed light on this situation. It was agreed that recent migration trends also exhibited more churn.

3.15 It was noted that there had been a fall in migration since the last set of projections due to government policies, the specific details of which could not have been predicted. It was observed that the policies related to the easier to control categories of tier 1 migrants and students, and that it was difficult to see where further substantial reductions could come from. Policies aimed at family migration (e.g. elderly relatives) were expected to lead to a slight drop but nothing in the range of the falls seen recently.

3.16 SD asked the panel whether the fall in migration had gone as far as it could. The panel suggested that there was probably not much scope for student or labour migrants to fall further especially given the accession of Romania and Bulgaria to the EU and the upcoming accession of Croatia. It was noted that corporate transfers, which are not included in the labour cap, are now the biggest part of the labour flow.

3.17 It was also noted that the policies enacted so far have not necessarily set up a downward trend but rather had taken a ‘bite’ out of migrant numbers. The panel discussed whether there was now any remaining ‘bite’ left in the policies. It was agreed that there was some downward pressure left but that it would probably exhaust itself soon. It was also noted that the tier 2 cap has not had much of an effect on migrant numbers.

3.18 The panel noted that the most recent drop in migration could mainly be attributed to students who are less likely to stay permanently, and that there is a lot of heterogeneity in the overall numbers. The possibility of a lag effect was mentioned, with the current reduction in student immigration leading to a drop in student emigration in the future.

3.19 It was suggested that there may be further bites on the university sector with the demise of the Post-Study Work Route (PSWR) likely to have an adverse effect on recruiting international students (especially at Masters level) and the cap on Tier 2 likely to hinder universities wanting to recruit non-EEA staff and researchers.

3.20 The question of whether policy changes by other governments were important was discussed, e.g. the forthcoming changes in Germany. The panel agreed that this was an important factor and that Germany was a key country to examine.

3.21 The issue of relative economic differentials was addressed and it was noted that the speed of economic recovery in the Eurozone versus the UK could be a factor. It was noted that there are particular economic issues in traditional target countries for Romanian migrants e.g. Spain.

3.22 The panel observed that more part time working reduces the availability of jobs and that the government’s welfare policies for getting people into work could have a displacement effect and lead to a downward pressure on migration. It was noted that, in contrast, demographic ageing was a large upward pressure on migration.

3.23 Specific issues relating to Bulgarian and Romanian migrants were then discussed in more detail. It was noted that there are 20,000 Bulgarian and Romanians in agricultural work in the UK and the issue of what would happen if they move out of agriculture as expected was brought up. The trend for Eastern European migrants to buy property and gain university educations in Spain was raised as example. It was agreed that it was reasonable to assume that Romanian and Bulgarian migrants would follow a similar route to A8 migrants in the UK, leading to the question of who will carry out agricultural work in the UK.

3.24 In order to predict what would happen regarding migration from Romania and Bulgaria in the long term, the panel discussed Portugal, which saw a 10 per cent emigration rate in the 1960s/70s and then a period of sudden inflow that subsequently settled down. It was suggested that this may be the long term pattern demonstrated by Romania and Bulgaria. It was also noted that both Romania and Bulgaria have low fertility rates and high emigration rates, which could lead to demographic disaster in these countries in the future. It was mentioned that the Slovakian inflows to Austria demonstrate a similar pattern to Portugal.

3.25 The panel discussed emigration from the UK. It was agreed that emigration of skilled British citizens to Australia, Canada and the USA was likely to increase slightly in the future with these workers therefore needing to be replaced in the UK.

3.26 It was asked whether anything could be learnt from the Scottish approach to migration, which differs from England and Wales. Esta Clarke (EC) replied that it was difficult to tell at this stage. BH added that England and Wales take the approach of limits to reduce migration, whereas in Scotland there is discussion of migration targets for population growth. The panel noted that the actual policy approaches available to Scotland are limited.

3.27 The panel mentioned that there are differences in the way migration is perceived in Scotland, with an expert citing the example of a Scottish phone-in where the majority of the comments on migration were positive. It was noted that there seemed to be a general pro-migration consensus of opinion in Scotland which may be the result of government policy.

3.28 One expert mentioned a survey which had compared the experiences of migrants in Southampton and Glasgow, and noted that the migrants in Glasgow had expressed higher levels of satisfaction with their situations. It was noted that there was a general consensus in Scotland that migrants are welcome and should be integrated. EC reiterated that both the devolved government and local governments in Scotland demonstrated a positive approach to migration. It was noted that Scotland has received its proportionate share of recent migrants (e.g. 10 per cent) which is a change from the past.

3.29 SD noted that when the experts were asked about the different constituent countries in the questionnaire, they had indicated that there were differences between the South of England and the rest of the UK rather than between the UK countries. The panel noted that it is important to look at where people arrive in the UK and whether it is related to demographic factors like ageing populations, or the labour market etc.

3.30 The panel noted that migration patterns in the last 10 years have been different from previous patterns due to the fact that recent migration has been primarily industry-lead by, e.g. for farms and processing, so migrants have moved to different parts of the country than in previous migration waves. It was noted that this was probably a special situation which would be unlikely to be repeated in the foreseeable future. It was also noted that Eastern European migrants are generally well-educated and have quickly transitioned to running businesses etc. in the UK.

3.31 The divergence of the experts’ responses to the asylum questions was discussed. The experts questioned why asylum seeker numbers have fallen so significantly and what can be learnt from this. It was noted that there has been a steep drop in asylum claims in the EU as a whole, with the drop in the UK steeper still, which indicates tightening of policies and less overall demand. Whether this is a global phenomenon or due to Europe taking a smaller share of global asylum seekers is not clear.

3.32 The panel discussed the fact that asylum claims rose in the 1990s due to wars and political instability in Eastern Europe and the Middle East. The drop after 2003-04 was ascribed to changes in Iraq, Afghanistan and Sri Lanka which meant that the main sources of asylum seekers were reduced. It was mentioned that Europe as a whole also re-evaluated its asylum systems, introducing rapid tracks and making appeals more difficult.

3.33 It was noted that asylum seeker movements are potentially very volatile and vary enormously depending on when and where there are conflicts and if there are strong traditional links to the receiving countries. For example, there was a large movement of asylum seekers from Yugoslavia to Germany in the late 1980s/early 1990s. The economic emergence of China and South America could also mean that asylum seekers would target these areas rather than the UK.

3.34 The panel discussed the fact that since the 1970s 2.7 to 3 per cent of the World’s population has been classed as migrants. Assuming that the global population continues to grow and that the percentage of migrants holds at around three per cent, this will produce extra migrants who will have to move somewhere. It was noted that migrants tend to move to neighbouring countries with better conditions, which means that future movements will likely depend a lot on development of the BRIC countries. Possible rises in migration to China, South America and India at the expense of migration to the UK were discussed, but it was also mentioned that the UK could start to receive more migrants from China and South America as their economies develop and ties are built with the UK.

3.35 It was noted that environmental change also needs to be taken into account. The panel questioned whether deterioration in some vulnerable parts of the world will lead to more people wanting to come to the UK (depending to some extent on the absorptive capacity of southern Europe) and whether new economic poles (such as the BRICs) will absorb more emigrating Britons.

3.36 BH observed that many of the pressures discussed had equal and opposite effects e.g. conflict, the policy differences between Scotland and England.

3.37 SD added further questions for the experts to discuss:

  • What time period should the short term assumption be set at?

  • The previous high and low migration variants were set at +/- 60,000 of the principal. Is it reasonable to keep this level consistent with previous projections given the requirements of policy makers and planners?

 
3.38 The panel suggested that five years would be a suitable duration for the short term assumptions due to economic circumstances and government policies on migration which mean that migration may stay fairly steady in the short term, even though the long term trend may be upwards.

3.39 The panel discussed how valid the use of time series extrapolation with trend is. It was noted that some changes are not trends but are just step changes.

3.40 It was suggested that there could be a need to look at more causal based modelling (e.g. economic factors) for the long term (2030-2040) due to changes in the population which would not be reflected in time series modelling. BH responded that it is important that ONS does not imply a level of precision that does not exist in examining possible modelling approaches.

3.41 The panel observed that age structure has a large effect on migration patterns. BH and SD added that the potential future use of migration rates would be beneficial from this perspective, especially given the projection horizon of 100 years.

3.42 It was suggested that ONS would need a reason for the high and low variants otherwise they could be misinterpreted. SD mentioned that the 2010-based NPP consultation had queried the variants but that no suitable alternative had been suggested and some users had asked for consistency with previous variants.

3.43 The experts mentioned that there was no ‘good’ way to set variants so to have a simple methodology which is broadly consistent with the evidence would be recommended. It was suggested that a figure of +/- X would be a reasonable approach, especially since there is no basis for a precise figure. It was also suggested that multiple approaches could be taken. BH added that ONS do publish a number of different variants looking at plausible versions of the future.

4. Mortality

Introduction

4.1 Julie Mills (JM) began the mortality presentation by describing the long term trends in mortality. He noted that life expectancy had increased slowly over the last half of the 19th Century followed by a more rapid increase for the first half of the 20th Century. Both males and females have shown a steady increase in life expectancy since the 1950s.

4.2 JM noted that the gap between male and female life expectancy was at its widest (six years) in 1960. It has since narrowed to four years.

4.3 Life expectancy at age 65 showed a slow increase up to the 1920s but has subsequently been more rapid.

4.4 JM then described the latest figures which indicate that life expectancy at birth in England and Wales in 2009-11 was 78.7 for males and 82.6 for females. It was noted that Denmark and the USA were the only countries from the selection with lower life expectancies than the UK. AG added that Hong Kong currently has the highest life expectancies in the world.

4.5 It was noted that recent improvements in life expectancy have been driven by falls in deaths from circulatory diseases and that cancer is now the leading cause group. Heart disease is still the leading specific cause of death for both males and females. Lung cancer is the second most common cause for males while dementia/Alzheimer’s is second for females.

4.6 JM highlighted the golden cohort, born in the 1930s, which has higher improvement rates at all ages than the surrounding cohorts for both males and females.

4.7 The methodology for the 2010-based assumptions was briefly described. Adrian Gallop (AG) explained that it was a four step process:

  1. Estimate current rates of mortality improvement by age and gender.

  2. Set target rates of improvement for the target year.

  3. Make assumptions on method and speed of convergence of current improvement rates to target rates and how improvement rates change after the target year.

  4. Apply successively to assumed base mortality rates.

 
Male improvements are assumed to tail off and a constraint is set so that they do not cross with females.

4.8 Comparisons were made between the assumed and observed percentage changes in smoothed death rates by age.

4.9 When the percentage changes of death rates using the old mid year estimates were compared with the rebased mid year estimates, there were some differences, particularly for older males, with the old estimates producing higher percentage changes.

4.10 Potential drivers for future mortality change were described. These were:

  • changes in biomedical technology,

  • effectiveness of health care systems,

  • behavioural changes related to health (declines in smoking prevalence, lifestyles and obesity),

  • emergence of new diseases e.g. HIV, SARS,

  • re-emergence of old diseases e.g. TB,

  • environmental change, disasters, wars,

  • changes in population composition; cohort effect, migrants.

 
4.11 The choice of the target rate of improvement was then addressed. AG noted that rates of improvement at older ages are the most important because these ages are where most deaths occur. Other factors to consider were that the standardised rate of improvement over the last 100 years was approximately 1.2 per cent pa and that the cohorts exhibiting the greatest improvement will be aged 100-110 in 25 years so will not contribute much to the overall rate of improvement in the target year. It was noted that there is debate as to whether future technical, medical and environmental changes will have greater or lesser impact than in the past.

4.12 A graph was shown which illustrated the 2010-based principal and variant improvement rates for 2035 compared with the improvement rates in 2010. The principal improvement rate was set at 1.2 per cent for all ages apart from the golden cohort. The smoothing to the target rates for both males and females was demonstrated with heat charts.

4.13 It was noted that the 2010-based projections projected greater increases in life expectancy at birth for the UK than most other countries.

4.14 JM summarised the questionnaire results. The predicted central estimates for male and female life expectancy in 2036 were 84 years for males and 87.4 years for females. These are similar to the predictions from the previous expert panel and are roughly equivalent to a target improvement rate of 1.5 per cent. For 2016, the predicted central estimates were 80 years for males and 83.9 years for females. This is close to the 2010-based projections.

4.15 JM then set out the topics for the expert panel to discuss:

  • Choice of target rate:
    Common target rate for all ages or vary by age?
    Same target rates for males and females or different? What level?
    Same target rates for all four countries of the UK or different?

  • Cohort patterns – will they persist? Will we see cohort patterns for younger ages?

  • Convergence/divergence/same differential between male and female mortality rates/expectation of life?

  • Effects of behavioural change.

  • Migrant mortality.

  • Socio-economic class differentials.

  • Mortality at oldest ages (90 and over).

  • Variants.

Discussion

4.16 The experts asked for more information on the effects of rebasing the population estimates. AG replied that rebasing would have led to higher rates of improvement for younger ages in the previous projections and lower rates for older ages, with males and females being affected similarly.

4.17 The panel also asked whether there could be differences in the quality of the 2011 population estimates between males and females. BH replied that there would be no systematic reason for the estimates to vary in quality between males and females. The fact that there are more women at older ages would mean that any absolute numbers would have less of an impact on women in percentage terms however.

4.18 The experts discussed why men in their 40s showed negative improvement rates. It was suggested that in the 1980s this may have been due to HIV, but it is unclear why the effect has continued. Suicide was suggested as a possible explanation with the panel noting that there are now more men living alone at these ages. It was also noted that a few hundred deaths at this age can make a large difference.

4.19 It was observed that ONS’ forecasts of constant rates of improvement imply an asymptotic life expectancy and that the UK projections have been identified as having very optimistic rates of improvement, which would explain why life expectancy has been predicted to improve faster in the UK than other countries. The experts noted that ONS would have to consider how to defend this. AG noted that other countries use different methods and it is unclear how they reach their final figures, and that some experts have suggested that actuaries have been underestimating mortality improvements. He noted that improvement rates in the past have been very rapid. It was agreed that there had been a tendency in the past to be too conservative.It was noted that studies have shown that it is possible to take projected life expectancy and calculate the improvement rates used to reach that life expectancy.

4.20 AG noted that it would be necessary to look at life expectancy at different ages and that there has been an ageing in the high rates of mortality improvement.

4.21 The panel queried how UK projections have compared with other countries and to what extent UK projections have been better than Eurostat ones. It was also noted that Southern European countries had been left out of the presentation slides. AG answered that this was because of language issues and an inability to locate the projections.
It was suggested that some Southern European countries showed surprising results e.g. Greece. AG replied that Southern European life expectancies have risen rapidly in recent years.

4.22 The issue of capturing the mortality of British expatriates was raised and whether a selected healthier group may have migrated in retirement. AG was asked whether this had been investigated using pensions paid abroad etc. AG replied that some work had been carried out in this area.  The panel wondered whether some people could appear in the denominator for rates but not in the numerator. AG replied that the denominators and numerators did not match perfectly but that people dying outside the UK would not be included in either. He explained that all data used in the projections come from deaths of people in the UK.

4.23 It was noted that projected improvements in male mortality converge rapidly with females and the question of whether male and female life expectancies would meet was raised. AG replied that the improvement rates for males and females are the same in the long term so the life expectancies do not meet. It was noted that at 110+ years old, the projected life expectancies can end up crossing over, so the projections are fine tuned in order to ensure that they converge but do not cross.

4.24 It was suggested that reversal in smoking trends between the sexes could cause life expectancies to cross over. AG noted that ONS looks at oddities compared with what has happened in the past.

4.25 It was also observed that occupation can have an effect on life expectancy with asbestos-related deaths being disproportionately male. AG agreed that male and female life expectancy would converge more in the future due to more similar lifestyles (e.g. the reduction of heavy industry).

4.26 The panel noted that more people will be living from 60 to 70 and from 70 to 80 etc. so it is important to get improvement rates right at these ages since they are the ones driving the projections. It was also suggested that ONS may want to set different improvement rates for males and females. AG replied that, in the past, most experts have agreed that it is reasonable for males and females to have the same improvement rates.

4.27 It was suggested that there is a high correlation between the differences in life expectancies between the sexes and the differences in smoking prevalence. Countries with the highest gaps between life expectancy e.g. Russia and Japan, tend to have a predominately non-smoking female population and high prevalence of smoking in males. It was noted that smoking affects cardiovascular and mental health.

4.28 The panel mentioned that many studies show smoking as a big explanatory factor and it is possible to be fairly confident about its effects, but other behavioural factors are less hard to predict e.g. obesity, alcohol and physical activity. It was noted that obesity seems to directly affect disability but not mortality.

4.29 Julie Mills (JM) mentioned that a recent Dutch cohort study had shown that diabetes and hypertension were big killers. The experts suggested that obesity-related diabetes tends to lead to people dying in their 60s and 70s rather than their 80s and 90s. JM mentioned that it is important to look at what has been listed as the underlying cause of death on death certificates and the experts noted that there is a need to better identify obesity as a cause of death because it does not appear on death certificates.

4.30 BH observed that the discussion appeared to be slightly at odds with the results from the questionnaire. The panel suggested that the effects of obesity vary with age. At younger ages, obesity has a negative effect but it may actually have a slight protective effect if weight is gained at older ages. It was also noted that obesity may have been underestimated as a cause of death in the past due to its links with smoking because ‘you can’t die twice’. It was suggested that the future effects of obesity may be mitigated however because more people will be affected so more research and policies will be targeted at it. Deaths from Alzheimer’s were also discussed in this vein.

4.31 It was noted that taking a cause-specific approach has not been successful in the past and that there is a danger in assuming that things we think are important now will continue to be so in the future. It was noted that some causes could even be considered similar to epidemics e.g. the effect of smoking on mortality is likely to almost totally disappear in the future as smoking rates continue to fall. It was agreed that it may be preferable to eschew a cause-specific approach and instead continue with the current approach.

4.32 The likely impacts of biomedical improvements were discussed. The recent effects of statins and aspirin were mentioned and it was noted that new drugs were making a big difference to mortality rates for certain conditions and that they can cause unexpected ‘blips’ in mortality which cannot be predicted. It was also noted that new drugs are becoming cheaper.

4.33 It was observed that if duration of survival after first heart attack is studied at an individual level the recent improvements in survival are actually quite small, but there are large improvements at a population-level, i.e. if a few months of life are added to a large number of people, the overall effect is large. It was suggested that these factors are likely to have a bigger impact in the future than they had in the past.

4.34 The panel noted that better social care makes an even larger difference than medical technology and a distinction needs to be drawn between ‘game changing’ drugs like statins which are cheap and widely available, and more ‘bespoke’ drugs which are only available to a limited number of people.

4.35 The rightward shift in the survival curve was addressed. It was noted that the further ahead in time, the greater the number of deaths there will be at ages for which there is little information. It was suggested that, given the sparse data at the very oldest ages, it may be better to not assume a maximum life span. AG noted that ONS has to hypothesise mortality rates for 125 year olds even though there are none in the population, so there is a huge amount of uncertainty at these ages. AG also noted that it is important to look at the high and low variants when researching for pensions etc.

4.36 It was noted that mortality rate curves have been very smooth since the 1950s which may be due to health care efficacy dampening yearly fluctuations. The extraordinary stability in the last half a century in terms of the absence of epidemics was also noted.

4.37 The issue of climate change was raised and the experts speculated whether heat wave mortality and cold winters could lead to more fluctuations. It was noted that bad winters tend to have a larger effect than hot summers.

4.38 It was observed that the topical issue of antibiotic resistance had not been addressed so far. AG noted that there are a number of risks that could drive life expectancy down in the future and that they were difficult to predict so would fit better with scenario-type analyses.

4.39 The experts agreed with the use of 100 years of past data given that the projection horizon is 100 years.

5. AOB

5.1 BH thanked the experts and noted that it was useful to discuss some of the emerging issues. He asked for feedback on the process, both practical and methodological. 
 
 

Appendix B: Analysis of the Results of the NPP Expert Advisory Group Questionnaire

The NPP Expert Advisory Panel of seven academic demographic experts met in April 2013. In an accompanying questionnaire, they were asked for their opinions on the likely future levels and trends in fertility, mortality and migration. This report summarises the main findings.

Fertility

The experts were asked for their views on UK fertility trends over the next 25 years.

Expert assessment of long-term UK fertility level

The experts were asked for their views on the most likely level of the TFR in 2036. Six out of seven experts thought that the TFR would be between 1.80 and 2.00 in 2036 (the remaining expert did not feel they had sufficient expertise in fertility to comment on this question). Four experts felt the TFR would be between 1.90 and 2.00 in 2036, a similar level to 2011 (1.91). These predictions were more uniform than in the previous round of projections.

There was no consensus among the experts around exactly what the TFR would be in 2036, and all commented on the difficulty of predicting TFR into the future, given the range of conflicting forces.

The average TFR predicted for 2036 was 1.93, which is substantially above the average predictions from previous projection rounds. This is also higher than the 2010 based projection of a TFR of 1.84 in 2034, which may imply that there is evidence for increasing the long term assumption. However it is worth noting that the membership of the panel changed between projection rounds, so it is unclear whether this increase is due to different experts making up the panel, or a change in the experts’ views.

On average, experts believed that there was a 67% chance of the TFR in 2036 lying between 1.71 and 2.10, and a 95% chance of it lying between 1.5 and 2.28, though these figures for the 95% confidence interval were affected by one expert’s very large confidence interval estimate. (Figures 1-1 and 1-2).

Figure 1-1: Respondents' estimates of the TFR in 2036 (and associated 67% confidence intervals)

Figure 1-1: Respondents' estimates of the TFR in 2036 (and associated 67% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.

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Figure 1-2: Respondents' estimates of the TFR in 2036 (and associated 95% confidence intervals)

Figure 1-2: Respondents' estimates of the TFR in 2036 (and associated 95% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.

Download chart

Expert assessment of UK fertility trends in the short-term

The advisory panel was asked to assess the likely trend in fertility up to 2016 with reasons, and to estimate the likely TFR in 2016.

Likely short-term trends in fertility

The experts did not reach consensus about the trajectory of fertility to reach the predicted 2016 levels, with opinion spread between small decreases in the immediate short term and a stabilisation. The reasons given for this were:

  • the impact of government policies,

  • uncertain impact of economic conditions,

  • changing patterns of immigration.

In terms of likely trends in age-specific fertility rates up to 2016, all experts believed that ASFRs for women under 20 would stabilise or decrease further. There was no consensus on the likely short term ASFR trend for women in their 20s but no expert felt it would change substantially. There was broad agreement that fertility would continue to increase for women in their 30s and those aged over 40.

Quantitative estimates for 2016

The seven experts were asked to quantify the most likely level of the TFR in 2016, together with plausible ranges which would cover roughly 67 and 95% of possible values. Figures 1-3 and 1-4 show the predictions for 2016.

Estimated TFRs for 2016 ranged from 1.80 to 1.95. Four were between 1.90 and 1.95, two experts predicted 1.80, and one expert did not give a prediction. The mean was 1.89, a similar prediction to the 2010 projection round average.

Figure 1-3: Respondents' estimates of the TFR in 2016 (and associated 67% confidence intervals)

Figure 1-3: Respondents' estimates of the TFR in 2016 (and associated 67% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.

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Figure 1-4: Respondents' estimates of the TFR in 2016 (and associated 95% confidence intervals)

Figure 1-4: Respondents' estimates of the TFR in 2016 (and associated 95% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.

Download chart

On average, experts believed that there was a 67% chance of the TFR lying between 1.76 and 1.97 in 2016, and a 95% chance of it lying between 1.74 and 1.99. This underlines the uncertainty inherent in estimating future fertility, even within a short timescale. However, comfort can be taken from the relative similarity of the 67 and 95% confidence intervals.

Underlying forces that may influence future fertility

The advisory panel was asked to consider six forces with the potential to affect fertility levels in the long-term (to 2036). By considering a range of arguments within each force they were asked to assess the overall likely impact on future family size. The experts emphasised that the effect of some forces were complex and sometimes conflicting.

“Changes in macro level conditions that influence costs of children” was the force that showed the greatest agreement between experts. All bar one felt it would have a small downward impact on fertility. This is in line with the opinion of the 2010 expert panel, and reflects concerns about the effects of the current economic climate on fertility. Among the macro-level factors, affordability of housing and the effect of government policies were the issues with the greatest expert consensus on the effect on fertility, which was thought to be negative.

The forces “Changes in population composition and differential trends in population subgroups” and “Changing bio-medical conditions” also both showed a good degree of consensus among the experts with the majority thinking that both factors would have a small upwards effect of fertility rates. The major driver of change for the population composition force was felt to be migration patterns and the fertility differentials between UK born and immigrant women. The experts noted that fertility among immigrant women still showed large differences, with some immigrant groups having fertility well below UK born women, whilst others were much higher.

Opinion was divided on the impact of the force “Trends in patterns of education, work and income (including the proportion of time dedicated to the professional side of life)”.  Of the seven experts, four felt it would have a small downwards effect, one suggested a large downwards effect and the final two experts felt there would be a small upwards effect. The reasons behind these differences were discussed, and it was felt that different aspects of the force would act differently, with higher costs of education potentially causing some women to delay childbearing, but for others childbearing being seen as an alternative to more expensive education.

The final two forces, “Trend in ideal family size and (the strength of) individual desires for children” and “Changing nature and stability of partnerships” were felt by the majority of experts to have little or no net impact on fertility rates. This does not mean that the forces would not have some effect, but that the effects they have will be minor, or will be conflicting.

In addition to the forces ONS asked the experts about, they were invited to supply any other forces they felt would be important in shaping future fertility. One expert felt that the longer term move towards greater gender equality would have an upward impact on fertility as combining childbearing and working became easier for more women. Housing shortages and environmental impacts (of climate change worldwide, connected to migration) were also felt to be factors that could affect UK fertility in the long term.

Mortality

The experts were asked for their views on expectations of life at birth in the UK, and on a series of arguments that might be thought likely to influence mortality, either upwards or downwards.

The average response by the experts for period expectation of life at birth in 2036 was 84.1 years for males and 87.4 years for females.  These compare with the proposed projection for 2036 of 84.0 years for males and 87.1 years for females. There was some divergence of views with regard to life expectancy for females between the experts, with two of the five estimates being outside the 67% confidence interval for the group average (Figure 1-5).

Figure 1-5: Respondents' estimates of period life expectancy for females in 2036 (and associated 67% confidence intervals)

Figure 1-5: Respondents' estimates of period life expectancy for females in 2036 (and associated 67% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.

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The majority of the panel was optimistic about future mortality improvements although they had differing views about period expectation of life at birth continuing to rise at the same rate as that seen over the last decade or so. Most were of the opinion that the rates of improvement in male mortality should be higher or maintained at 1.2% per year or that it should be around 1.5%. One of the experts thought that the rates of improvement for males should be reduced to 1.0%. The opinions were quite similar with regard to rates of improvement in female mortality: the majority of experts agreed with increases of 1.2% per year or higher and one expert felt they should be lower at 1.0% a year.

The main forces thought most likely to affect future mortality levels were changes in bio-medical technology and behavioural changes related to health. The majority opinion of the expert panel was that these two forces should have a small upward influence on life expectancy with two experts reporting a large upward influence for the forces.

The experts generally felt that possible new infectious diseases and the resurgence of old diseases would have little or no influence on life expectancy although comment was made surrounding antibiotic resistant bacteria. They were also of the opinion that changes in population composition and differential trends in population subgroups would have little impact. The majority of the panel thought that the level of obesity in the UK would increase over the next 25 years, but that this would have relatively little effect on future life expectancy.

Migration

The experts were asked about their views on the levels of international migration to and from the UK in 2016 and 2036 (that is, five years and twenty-five years into the future from the 2011 estimates, which were the latest available at the time).

Experts' views on migration in the long-term

With respect to immigration to the UK, four experts thought that the level in 2036 would be somewhat lower than the average of 2007-2011 estimates (that is, between 400,000 and 500,000 per year), two experts thought that the level would be somewhat higher (between 600,000 and 700,000 per year), and one thought it would be much higher (greater than 700,000 per year). The average response for the expected level of annual immigration to the UK in 2036 was 623,000, with an average 67% confidence interval of 480,000 to 805,000.

With respect to emigration from the UK, five experts thought that the level in 2036 would be roughly similar to the average of 2007-2011 estimates (that is, between 300,000 and 400,000 per year), whilst two thought it would be higher (between 400,000 and 500,000 per year). The average response for the expected level of annual emigration in 2036 was 397,000, with an average 67% confidence interval of 287,000 to 447,000.

The average annual net migration derived from the experts’ responses for 2036 was a net inflow of +162,000 per year (with an average 67% confidence interval of 120,000 to 280,000). This is close to the proposed 2012-based long-term assumption for net migration to the UK of +165,000 per year. Net international migration to the UK derived from the experts’ assessment of likely levels of immigration and emigration in 2036 are shown in Figure 1-6, together with associated 67% confidence intervals.

Figure 1-6: Respondents' estimates of total net migration in 2036 (and associated 67% confidence intervals)

Figure 1-6: Respondents' estimates of total net migration in 2036 (and associated 67% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.
  2. Estimates provided with either only an upper or only a lower limit are included.

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The experts were also asked to consider five overall forces with the potential to affect levels of net migration to the UK in the long-term and assess the importance and likely impact of each force upon future migration:

  • The main motives for international migration – work, study, joining/accompanying family.

  • Migration pressure resulting from changes in the countries of origin.

  • The attractiveness of the UK as a country of residence.

  • Costs of migration (in the broader sense).

  • Controls on migration flows (referring to both the tightening and removal of controls).

The majority of experts considered the first two forces to have a small upward effect or no influence on total net migration, and forces three and four to have a downward effect or no influence. Almost all experts considered the last force, controls on migration, to have a downwards influence on migration. Other forces identified by the experts were conflict and political instability, environmental change, the economy and labour market policies.

Experts’ views on migration in the short-term

With respect to immigration to the UK, four experts thought that the level in 2016 would be roughly similar to that estimated for 2011 (that is, between 500,000 and 600,000 per year), whilst two thought that the level would be lower (between 400,000 and 500,000 per year). The remaining expert thought it would be much higher (greater than 700,000 per year).The average response for the expected level of annual immigration to the UK in 2016 was 578,000, with an average 67% confidence interval of 488,000 to 672,000.

With respect to emigration from the UK, six experts thought that the level in 2016 would be roughly similar to that estimated for 2011 (that is, between 300,000 and 400,000 per year), and one thought it would be higher (between 400,000 and 500,000 per year). The average response for the expected level of annual emigration from the UK in 2014 was 334,000, with an average 67% confidence interval of 294,000 to 387,000.

The annual net migration derived from the experts’ responses for 2016 was an inflow of +183,000 per year (with an average 67% confidence interval of 140,000 to 232,000). This is somewhat higher than the corresponding experts’ average for 2036 (+162,000 per year) and the 2012-based long-term assumption of +165,000, but is close to the assumed short term run-in figure for 2015-16 of +183,500. Net international migration to the UK derived from the experts’ assessment of likely levels of immigration and emigration in 2016 are shown in Figure 1-7, together with associated 67% confidence intervals.

Figure 1-7: Respondents' estimates of total net migration in 2016 (and associated 67% confidence intervals)

Figure 1-7: Respondents' estimates of total net migration in 2016 (and associated 67% confidence intervals)

Notes:

  1. Estimates provided without confidence intervals were excluded.
  2. Estimates provided with either only an upper or only a lower limit are included.

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Specific scenarios 

The experts were also asked to consider the effects of certain specific situations on migration:

The economy 

There were mixed views on the effects of the economy on migration over the next five years. Two experts thought it would have an upwards influence on net migration, two that it would have a downwards influence and two that it would have little or no effect.

Controls and Government policies on EU and non-EU migration

There were also mixed views on EU and non-EU migration in relation to the effects of controls and government policies on migration.

All but one expert thought that net migration from the EU would be roughly similar or somewhat higher over the next five years while views on non-EU net migration were more mixed, with three experts thinking it would be somewhat lower, two that it would be somewhat higher and two that it would be roughly similar.

In the long-term, four experts thought that EU migration would be higher than now, two that it would be lower, and one that there would be no change. Regarding immigration from outside the EU, three experts thought it would be higher, three lower, and one that there would be no change.

Reasons for migration to UK

The experts also gave their opinions on the current main reasons for migration to the UK. Four experts thought that migration for study would be lower in five years time and three thought it would be similar. Three experts thought that migration for work would be lower, two that it would be higher and two that it would be about the same. Two experts thought that migration for family reasons would be higher, one lower and four that it would be about the same.

EU accession countries

The experts’ predictions for total migration from the 13 countries which joined the EU between 2004 and 2013 (Bulgaria, Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Romania, Slovakia, and Slovenia) ranged from 68,000 to 100,000 for 2016 and from 30,000 to 150,000 for 2036.

Regional differences

Generally, the experts thought that migration would continue to be concentrated in London and the South of England. They also noted that the results of the Scottish independence referendum could have an effect on future migration patterns.

Appendix C: Changes to State Pension Age

Pensionable ages for men and women

Between 2010 and 2020, state pension age will change from 65 years for men and 60 years for women, to 66 years for both sexes.

  • Any woman born before 6 April 1950 will attain pensionable age when she reaches the age of 60.

  • For women born between 6 April 1950 and 5 December 1953, the date that pensionable age will be attained can be found in changing the pension age table 1-5.

  • For men and women born between 6 December 1953 and 5 October 1954, the date that pensionable age will be attained can be found in changing the pension age table 1-6.

Table 1-5: Date State Pension age will be achieved for women born between 6 April 1950 and 5 December 1953

Date of birth Date State Pension age reached
6 April 1950 – 5 May 1950 6 May 2010
6 May 1950 – 5 June 1950  6 July 2010
6 June 1950 – 5 July 1950  6 September 2010
6 July 1950 – 5 August 1950  6 November 2010
6 August 1950 – 5 September 1950  6 January 2011
6 September 1950 – 5 October 1950  6 March 2011
6 October 1950 – 5 November 1950  6 May 2011
6 November 1950 – 5 December 1950  6 July 2011
6 December 1950 – 5 January 1951  6 September 2011
6 January 1951 – 5 February 1951  6 November 2011
6 February 1951 – 5 March 1951   6 January 2012
6 March 1951 – 5 April 1951  6 March 2012
6 April 1951 – 5 May 1951  6 May 2012
6 May 1951 – 5 June 1951  6 July 2012
6 June 1951 – 5 July 1951  6 September 2012
6 July 1951 – 5 August 1951  6 November 2012
6 August 1951 – 5 September 1951  6 January 2013
6 September 1951 – 5 October 1951  6 March 2013
6 October 1951 – 5 November 1951  6 May 2013
6 November 1951 – 5 December 1951  6 July 2013
6 December 1951 – 5 January 1952  6 September 2013
6 January 1952 – 5 February 1952  6 November 2013
6 February 1952 – 5 March 1952  6 January 2014
6 March 1952 – 5 April 1952  6 March 2014
6 April 1952 – 5 May 1952  6 May 2014
6 May 1952 – 5 June 1952  6 July 2014
6 June 1952 – 5 July 1952  6 September 2014
6 July 1952 – 5 August 1952  6 November 2014
6 August 1952 – 5 September 1952  6 January 2015
6 September 1952 – 5 October 1952  6 Mar 2015
6 October 1952 – 5 November 1952  6 May 2015
6 November 1952 – 5 December 1952  6 July 2015
6 December 1952 – 5 January 1953  6 September 2015
6 January 1953 – 5 February 1953  6 November 2015
6 February 1953 – 5 March 1953  6 January 2016
6 March 1953 – 5 April 1953  6 March 2016
6 April 1953 – 5 May 1953  6 July 2016
6 May 1953 – 5 June 1953  6 November 2016
6 June 1953 – 5 July 1953  6 March 2017
6 July 1953 – 5 August 1953  6 July 2017
6 August 1953 – 5 September 1953  6 November 2017
6 September 1953 – 5 October 1953  6 March 2018
6 October 1953 – 5 November 1953  6 July 2018
6 November 1953 – 5 December 1953  6 November 2018

Table source: Work and Pensions

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Table 1-6: Date State Pension age will be achieved for men and women born between 6 December 1953 and 5 October 1954

Date of birth Date State Pension age reached
6 December 1953 – 5 January 1954  6 March 2019
6 January 1954 – 5 February 1954  6 May 2019
6 February 1954 – 5 March 1954  6 July 2019
6 March 1954 – 5 April 1954  6 September 2019
6 April 1954 – 5 May 1954  6 November 2019
6 May 1954 – 5 June 1954  6 January 2020
6 June 1954 – 5 July 1954  6 Mar 2020
6 July 1954 – 5 August 1954  6 May 2020
6 August 1954 – 5 September 1954  6 Jul 2020
6 September 1954 – 5 October 1954  6 September 2020
6 October 1954 – 5 April 1968 66th birthday

Table source: Work and Pensions

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State pension age will then increase progressively from 66 years to 68 years for both men and women between 2034 and 2046.

  • Any person born after 5th October 1954 but before 6th April 1968 will attain pensionable age when he or she reaches the age of 66.

  • For persons born between 6th April 1968 and 5th April 1969, the date that pensionable age is attained is shown in changing the pension age table 1-7.

  • Any person born after 5th April 1969 but before 6th April 1977 will attain pension age when he or she reaches the age of 67.

  • For persons born between 6th April 1977 and 5th April 1978, the date that pensionable age will be attained can be found in changing the pension age table 1-8.

  • Any person born after 5th April 1978 will attain pensionable age when he or she attains the age of 68.

Table 1-7: Date State Pension age will be achieved for men and women born between 6 April 1968 and 5 April 1969

Date of birth Date State Pension age reached
6 April 1968 – 5 May 1968  6 May 2034
6 May 1968 – 5 June 1968  6 July 2034
6 June 1968 – 5 July 1968  6 September 2034
6 July 1968 – 5 August 1968  6 November 2034
6 August 1968 – 5 September 1968  6 January 2035
6 September 1968 – 5 October 1968  6 March 2035
6 October 1968 – 5 November 1968  6 May 2035
6 November 1968 – 5 December 1968  6 July 2035
6 December 1968 – 5 January 1969  6 September 2035
6 January 1969 – 5 February 1969  6 November 2035
6 February 1969 – 5 March 1969  6 January 2036
6 March 1969 – 5 April 1969  6 March 2036
6 April 1969 – 5 April 1977  67th birthday

Table source: Work and Pensions

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Table 1-8: Date State Pension age will be achieved for men and women born between 6 April 1977 and 5 April 1978

Date of birth Date State Pension age reached
6 April 1977 – 5 May 1977  6 May 2044
6 May 1977 – 5 June 1977  6 July 2044
6 June 1977 – 5 July 1977  6 September 2044
6 July 1977 – 5 August 1977  6 November 2044
6 August 1977 – 5 September 1977  6 January 2045
6 September 1977 – 5 October 1977  6 March 2045
6 October 1977 – 5 November 1977  6 May 2045
6 November 1977 – 5 December 1977  6 July 2045
6 December 1977 – 5 January 1978  6 September 2045
6 January 1978 – 5 February 1978  6 November 2045
6 February 1978 – 5 March 1978  6 January 2046
6 March 1978 – 5 April 1978  6 March 2046
6 April 1978 onwards  68th birthday

Table source: Work and Pensions

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Sources: Pensions Act 1995 Chapter 26 Part II Section 126 and Schedule 4; Pensions Act 2007 Chapter 22 Part I Section 13 and Schedule 3; Pensions Act 2011 Part 1 Section 1 and Schedule 1.

Calculation of populations of working age and pensionable age for national population projections

  • From 2004 to 2009, all women aged 60 to 64 are of pensionable age. From 2021 to 2033, all women aged 60 to 65 are of working age. From 2010 to 2020, the number of women aged 60 to 65 who are of pensionable age is calculated using changing the pension age table 1-9.

  • Similarly, from 2021 to 2033, all persons aged 66 and over are of pensionable age. From 2036 to 2043, all persons aged 66 are of working age and all persons aged 67 and over are of pensionable age. From 2034 to 2035, the number of men and women aged 66 who are of pensionable age is calculated using changing the pension age table 1-10.

  • From 2046 onwards, all persons aged 68 and over are of pensionable age and all persons aged 67 are of working age. From 2044 to 2045, the number of men and women aged 67 who are of pensionable age is calculated using changing the pension age table 1-10.

Table 1-9: Proportion of women aged 60 to 65 taken to be of pensionable age, 2010 to 2020

Age 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
60 0.847 0.351 0 0 0 0 0 0 0 0 0
61 1 1 0.847 0.350 0 0 0 0 0 0 0
62 1 1 1 1 0.847 0.351 0 0 0 0 0
63 1 1 1 1 1 1 0.764 0.014 0 0 0
64 1 1 1 1 1 1 1 1 0.266 0 0
65 1 1 1 1 1 1 1 1 1 0.603 0.099

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Table 1-10: Proportion of men and women aged 66 to 67 taken to be of pensionable age, 2034 to 2045

Age 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
66 0.847 0.351 0 0 0 0 0 0 0 0 0 0
67 1 1 1 1 1 1 1 1 1 1 0.847 0.351

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