Results of the National Population
Projections Expert Group Questionnaire
Chris Shaw
ONS
Background to NPP Expert Group
• Aim to have a formal way of feeding expert views into
assumption setting process
• Group set up via BSPS in 2005
• Group is advisory
• Has now contributed to last two sets of national projections
through
– Questionnaires
– Formal meetings
• Details published
– GAD website
– Projections reference volume
Membership
• David Coleman (University of Oxford)
• John Hollis (Greater London Authority)
• Mike Murphy (London School of Economics)
• Phil Rees (University of Leeds)
• John Salt (University College London)
• Robert Wright (University of Strathclyde)
Achievements
• NPP assumptions have moved closer to expert
views
– may partly be coincidental!
– but influential on mortality thinking
• Reinforced current choice of variant assumptions
• Provided input to stochastic forecasting work
• ONS now have improved understanding of why
experts think what they do
Respondents’ estimates of the TFR in 2030
2.6
2.4
2.2
TFR
2.0
1.8
1.6
1.4
1.2
1.0
0.5
Respondent
Average
67% Confidence Interval
Respondents’ estimates of period life
expectancy at birth for males in 2030
92
90
Life expectancy
88
86
84
82
80
78
76
0.5
Respondent
Average
67% Confidence Interval
Respondents’ estimates of total net
migration in 2030
400
350
300
Thousands
250
200
150
100
50
0
-50
0.5
-100
Respondent
Average
67% Confidence Interval
Key UK indicators at 2030
ONS
2006-based
principal
Expert panel
average
TFR
1.84
1.78
Male period life expectancy at
birth
82.6
82.9
Female period life expectancy
at birth
86.1
86.0
+190,000
+199,000
Annual net migration
Uncertainty at 2030
ONS assumptions
(High variant
– low variant)
Expert panel average
67% confidence
interval (high – low)
TFR
0.40
0.50
Male period life
expectancy at birth
3.7
4.1
Female period life
expectancy at birth
2.4
3.7
120,000
165,000
Annual net migration
2007 questionnaire
• UK panel piloted questionnaire being developed by
Professor Wolfgang Lutz, leader of the World
Population Programme at IIASA
• Aims to
– provide a rigorous framework for the assessment of
expert opinion
– by assessing the validity & importance of arguments
about future trends
• Questionnaire long, complex and imperfect!
• But has yielded rich source of qualitative data
Major forces shaping fertility
% weighting
Min
Max
Desire for children
23
5
60
Education & work
17
10
30
Macro level conditions
(childcare, housing …)
18
5
30
Stability of partnerships
18
10
25
Bio-medical conditions
9
5
15
Population composition
15
10
20
100
A strong desire for two child families will continue
because of the value attached to siblings.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
A strong desire for two child families will continue
because of the value attached to siblings.
Importance of argument
A large upward influence on family size
A small upward influence on family size
Little or no influence on family size
A small downward influence on family size
A large downward influence on family size
Don't know
0
1
2
3
4
Number of respondents
5
6
Disagreement among experts (example 1)
It is part of human nature to want at least two children. This is unlikely to
change in future.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
Major forces shaping mortality
% weighting
Min
Max
Bio-medical technology
28
15
50
Health care systems
17
10
30
Behavioural changes
28
10
53
New/resurgent diseases
9
5
15
Environmental changes
8
5
15
Population composition
9
0
20
100
Major forces shaping mortality
UK Panel IIASA (18 world
experts)
Bio-medical technology
28
25
Health care systems
17
24
Behavioural changes
28
25
New/resurgent
diseases
Environmental changes
9
7
8
8
Population composition
9
11
100
100
Increased understanding of bio-medical ageing processes
will allow us to develop effective anti-ageing strategies.
Validity of argument
Very likely to be right
More right than wrong
Don't know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
Increased understanding of bio-medical ageing processes
will allow us to develop effective anti-ageing strategies.
Importance of argument
A large upward influence on life expectancy
A small upward influence on life expectancy
Little or no influence on life expectancy
A small downward influence on life expectancy
A large downward influence on life expectancy
Don't know
0
1
2
3
4
Number of respondents
5
6
Smoking prevalence will continue to decline.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
Smoking prevalence will continue to decline.
Importance of argument
A large upward influence on life expectancy
A small upward influence on life expectancy
Little or no influence on life expectancy
A small downward influence on life expectancy
A large downward influence on life expectancy
Don't know
0
1
2
3
4
Number of respondents
5
6
Major forces shaping migration
% weighting
Min
Max
Motives for migration
(work, family formation, study)
18
10
25
Changes in countries of origin
20
10
30
Attractiveness of UK
30
10
50
8
5
15
23
10
50
Costs of migration
Barriers against migration
100
There will be an increase in the total number of people
wishing to migrate to and from the United Kingdom for
work related reasons.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
There will be an increase in the total number of people
wishing to migrate to and from the United Kingdom for
work related reasons.
Importance of argument
A large upward influence on total net migration
A small upward influence on total net migration
Little or no influence on total net migration
A small downward influence on total net migration
A large downward influence on total net migration
Don't know
0
1
2
3
4
Number of respondents
5
6
Population ageing in the UK will result in a shortage of
young labour which will increase the demand for
immigrants.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
Population ageing in the UK will result in a shortage of
young labour which will increase the demand for
immigrants.
Importance of argument
A large upward influence on total net migration
A small upward influence on total net migration
Little or no influence on total net migration
A small downward influence on total net migration
A large downward influence on total net migration
Don't know
0
1
2
3
4
Number of respondents
5
6
Of over 90 arguments, there was only one which
the experts unanimously agreed was invalid.
There is likely to be a move in the direction of “professional parenthood” where
some couples will specialize in raising larger families and receive compensation
equivalent to that of other professional services, while other women become
entirely work-oriented.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
4
3
Number of respondents
5
6
Disagreement among experts (example 2)
Global climate change will lead to a decline in food production in certain parts
of the world and, as a result, uncontrolled mass migration and conflicts will
increase mortality in this country.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
Disagreement among experts (example 3)
The economic consequences for the poorest countries of substantial outmigration will put moral pressure on developed countries to limit immigration.
Validity of argument
Very likely to be right
More right than wrong
Do not know / ambivalent
More wrong than right
Very likely to be wrong
0
1
2
3
4
Number of respondents
5
6
Factors considered to be valid by the majority of the
panel and considered to have the potential to impact on
future levels.
Fertility
Factors that could have an upwards impact on fertility:
• Increasing social acceptability of having children at older ages.
• Government being likely to improve financial support for children
through child subsidies and tax benefits.
• Increases in union dissolution and re-formation leading to additional
children in new partnerships.
• Medically assisted conceptions solving more fecundity problems in
future.
Factors considered to be valid by the majority of the
panel and considered to have the potential to impact on
future levels.
Fertility
Factors that could have an downwards impact on fertility:
• Family formation being postponed due to time spent in education.
• Fewer grandmothers available to help with childcare (due to
increased female labour force participation and increasing
retirement age).
• Women delaying pregnancy to older ages where there is a higher
risk of not getting pregnant.
• Decreasing proportion of unplanned births due to improvements in
contraception.
• Convergence in fertility rates of ethnic minority women resident in
the UK with fertility rates of indigenous women.
Factors considered to be valid by the majority of the
panel and considered to have the potential to impact on
future levels.
Mortality
Factors that could have an upwards impact on life expectancy:
• Greater understanding of bio-medical ageing processes leading to
•
•
•
•
•
•
the development of effective anti-ageing strategies.
Breakthroughs in the understanding of carcinogenic processes
leading to reduced mortality from cancer.
Medical advances leading to previously life-threatening diseases
becoming containable.
Progress in preventive medicine.
Better information about health.
A continued decrease in smoking prevalence.
Effective and easily affordable new technologies.
Factors considered to be valid by the majority of the
panel and considered to have the potential to impact on
future levels.
Mortality
Factors that could diminish or reverse increases in life
expectancy:
• Increasing drug resistance to known infectious diseases.
• Negative impact on health of increased stress levels.
• Majority of immigration will be from counties with higher
mortality than UK.
Factors considered to be valid by the majority of the
panel and considered to have the potential to impact on
future levels.
Migration
Factors that could have an upwards impact on net migration:
• Likelihood of increasing migration to and from the UK for work
•
•
•
•
related, family reunification/formation and education reasons.
High population growth in developing countries.
Population ageing in the UK.
The relative attractiveness of the UK as a country of destination (for
economic and other reasons);
With increasing globalisation, the increasing ease of movement
from one country to another.
Factors considered to be valid by the majority of the
panel and considered to have the potential to impact on
future levels.
Migration
Factors that could have a downwards impact on net migration:
• Increases in retirement emigration from the UK.
• The likelihood of new EU countries and developing countries
‘catching-up’ in terms of economic growth;
• Problems with integration leading to more restrictive immigration
policies.