Session 7: Population projections for
national populations
• 7.1. Spectrum
• 7.2. Evaluation of projection results
• 7.3. Accounting for uncertainty
– choosing alternative projection scenarios
• 7.4. Lab time
7.1.2. Using Spectrum
SPECTRUM is a suite of easy to use policy models which provide
policymakers with an analytical tool to support the decision making
process.
SPECTRUM consists of several software models including:
•DemProj: Demography
•FamPlan: Family Planning
•LiST: Lives Saved Tool (Child Survival)
•AIM: AIDS Impact Model
•Goals: Cost and impact of HIV Intervention
•Resource Needs Module: Costs of implementing an HIV/AIDS program
•RAPID: Resources for the Awareness of Population Impacts on
Development
•Safe Motherhood Model
•Allocate
7.1.2. Using Spectrum
SPECTRUM is at version 4.51.
As it under continuing development, one should check for updates
online:
http://www.futuresinstitute.org/spectrum.aspx
7.1.2. Using Spectrum
Spectrum
7.1.2. Using Spectrum
• Advantages:
– Reliable and well tested
– Appealing user-interface
– User base is large, but concentrated among health and
policy professionals (UNAIDS)
– Support, on-site Training available
• Disadvantages
– Complex package due to integration into a variety of
other tools (AIDS, POLICY etc.)
– Obtaining results can be cumbersome
7.1.2. Using Spectrum
• Steps:
•
•
•
•
1.
2.
3.
4.
Projection parameter settings
Data input
Executing the projection
Obtaining, saving the results
Hands-on exercise
• Preparing a cohort-component projection
with Spectrum
Hands-on exercise
• Executing the sample projection and examining the
results
• Preparing a new projection
• Adding data
• Obtaining results from Excel
Using Spectrum 1
Sample.pjn
Using Spectrum 2
Using Spectrum 3
Projection menu
group
Using Spectrum 4
Set last year
Uncheck AIDS
Using Spectrum 5
Using Spectrum 6
Using Spectrum 7
Using Spectrum 8
Using Spectrum 9
Using Spectrum 10
Using Spectrum 11
Using Spectrum 12
Using Spectrum13
Using Spectrum 14
Trouble shooting Spectrum
• Spectrum stores results in files with the
extension *.dp
• By renaming the file to *.csv, it can directly
be opened by Excel
7.2. Evaluation of projection results
Projections are about the future, and therefore are invariably
incorrect. It would not be useful to evaluate them in terms of their
correctness (accuracy). Instead, one should assess them differently:
1. Sound Methodology
–
2.
Internal Consistency
–
–
3.
The projection makes sense relative to the characteristics and
assumptions of the methods
The projection makes sense compared to historical demographic
patterns
The projection makes sense compared to local socioeconomic/
cultural characteristics
External Consistency
–
The projection makes sense compared to contextual and/or
comparison areas
7.3. Accounting for uncertainty -Choosing alternative projections
scenarios
•
•
•
•
•
Reasons for uncertainty
How to account for uncertainty?
Construct scenarios
Project past variability
Expert opinions
Reasons for uncertainty
• Open future – several options for future trends
• Input data
• Assumptions
How to account for uncertainty?
• Construct scenarios
• Probabilistic projections:
– Project past variability
– Expert opinions
Scenarios
• Common scenarios
•
•
•
•
Constant fertility
Constant Mortality
No migration
Instant replacement
Hands-on exercise:
• Preparing and comparing different projection
variants
Hands-on exercise: Scenarios
• Spectrum: Comparison Projections
• Start by creating a Projection, using data in Spectrum.
• You may modify the data as you wish: Set fertility to
constant, for example. Name it accordingly: BeninConst.
• Or simply use the medium variant available in Spectrum
as a starting point. Name it BeninMedium.
• Select an appropriate base year (2010?).
• Select an appropriate last year (2050?)
• Inspect the settings. Save the projection
• Next add more scenarios.
Hands-on exercise: Scenarios
• Add another scenarios.
• You could just create another projection input file,
apply your scenario setting and save it with an
appropriate name.
• There is a shortcut: Open the file you just saved
again. Spectrum gives you a choice. Click on Load
and rename.
Hands-on exercise: Scenarios
• We want the second scenario to keep fertility levels
constant at base level. Name the second scenario
BeninConstant.
• Spectrum has now two projections loaded:
BeninMedium and BeninConstant. BeninConstant is
right now only a copy of BeninMedium, so we have
to make changes to the fertility settings in
BeninConstant.
• Make sure that BeninConstant is set to be the active
projection.
Hands-on exercise: Scenarios
• In order to keep the fertility constant, you can
either copy the base fertility to the projection years,
or use Spectrum’s copy and duplicate functions:
• Highlight the fertility and click Duplicate.
• Check if the fertility has been changed: Go to results
and look at the fertility chart.
• Note that there are now two fertility trends, one
named BeninMedium, and one named
BeninConstant.
Hands-on exercise: Scenarios
• Now you may add even more scenarios.
• As the first scenario (BeninMedium) is the reference
scenario, set BeninMedium to be the active
projection.
• Now re-load BeninMedium, and chose Load and
rename.
• Rename it to BeninInstant.
Hands-on exercise: Scenarios
• What do the scenarios reveal about the
demographic future of the country chosen?
• Discuss the results.
7.4.Lab time
Other software
• RUPEX US Census Bureau Rural-Urban
Projection Program with EXCEL interface
• United Nations MORTPAK projection program
PROJCT
• LIPRO multi-state projection program
(LIfestyle PROjections)
USCB RUPEX
Description
The program uses the cohort component method for projecting the
population by age and sex.
The projection is made following cohorts by single years of age, even if
all or some of the input data are in five year age groups.
Using interpolated values of central death rates from life tables, RUP
estimates the number of deaths and subtracts them from each cohort.
It also takes into account internal and international migration. Every year
births are estimated using fertility rates and the female population in
reproductive ages. The annual number of births constitute new
population cohorts that are followed through in the future.
USCB RUPEX
Steps using RUPEX:
– 1.
Data input
– 2.
Projection parameter settings
– 3.
Executing the projection
– 4.
Obtaining, saving the results
USCB RUPEX
The program provides output of a wide variety of demographic measures
for any specified year of the projection period.
These outputs include:
a)
b)
c)
d)
e)
f)
Population by sex and age (single years, 5-year age groups, special groups)
and summary measures of age (e.g., percentages, sex ratios, median ages,
dependency ratios).
Summary vital rates (e.g., crude rates, life expectancy, infant mortality rates,
and total fertility rates).
Life tables.
Net numbers of migrants or migration rates by age and sex.
Number of deaths, by age and sex.
Number of births, by age of mother, and age-specific fertility rates.
USCB RUPEX
– Advantages:
• Reliable and well tested methodology
• Large user base
• Professional support
• On-site Training available
• Integration with analysis tools
– Disadvantages
• User interface somewhat non-intuitive (Excel based)
• Data format of input file text based and not self
explanatory
• Still in testing for Windows Vista/Win7
United Nations
MORTPAK Population Projection
LIPRO
• Multistate projection program developed by
NIDI, Netherlands
• Although originally developed for household
projections, the LIPRO computer program can
be used for a wide range of calculations in
multistate demography. LIPRO has been
extensively used for various applications, in
the Netherlands as well as in many other
countries.
LIPRO
• Consistency algorithms exist and can be
expanded.
• Powerful, but demanding.
• No further development
• Runs only under Windows XP
LIPRO
LIPRO
• Projection data must be prepared outside:
age-specific rates of change for each
region/unit. Their evolution over time can be
controlled through a scenario module.
Alternatively, the number of events by age
and sex can be inputted; LIPRO will then
calculate the rates/probabilities.
Challenge: Age-specific migration rate matrix:
Origin and destination, by age.
LIPRO
•
•
•
•
•
Belgium - LIPRO household typology
China - population projections Shanghai
Marital status projections for England & Wales.
Spain - population projections Catalonia
Paper on: Internal migration scenarios and
regional population projections for the European
Union. International Journal of Population
Geography
• http://www.nidi.knaw.nl/Pages/NID/24/841.bGFuZz1VSw.html
Thank you