Microsimulation in Canada:
Lessons from Statistics
Canada
Chantal Hicks
British Society for Population Studies
University of Sussex, September 11, 2009
Note
 Opinions represented in this paper represents
my views and are not the views of Statistics
Canada
 More emphasis on the models with which I’ve
been involved
2
Statistics Canada • Statistique Canada
September 11, 2009
Microsimulation in the
Government of Canada
Microsimulation in the rest of
Government of Canada
 Human Resources and Skills
Development Canada
• Static tax/transfer model
(SIMTAB)
• Dynamic pension model
(DYNACAN). Funding ended
June 2009
• Employment Insurance model
 Health Canada and Public
Health Agency of Canada
•
•
•
•
Pharmacare model
Human resource models
First Nation model
Pandemic Flu model
 Department of Finance
• Static tax/transfer model
(TTSIM)
• Corporate tax model
4
Statistics Canada • Statistique Canada
September 11, 2009
Overlap exists
 At least 3 models which calculate taxes and
transfers starting from the same public use
survey (Survey of Labour and Income
Dynamics)
5
Statistics Canada • Statistique Canada
September 11, 2009
Modeling at Statistics Canada Done by
Four Groups
 Modeling Division
• Modelling technologies
• Socio-economic models
• Infectious disease models
 Health Analysis Division
• Health and disease models
6
 Demography Division
• Demographic projection
models
 Human Resources
Development Division
• Personnel models
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
PERSIM
1988
1992
7
POHEM
(Modgen)
1996
2000
PopModM
Caremod
RiskPaths
IDMM
POHEM
(APL)
Michael
Wolfson
Arrives
HIVMM
Modgen
SPSD/M
Public release
1984
LifePaths
2004
2008
DEMOSIM
XECON
FADEP
Statistics Canada • Statistique Canada
CVMM
September 11, 2009
Social Policy Simulation Database and
Model (SPSD/M)
 First model developed at Statistics Canada
 Static tax/transfer model
 Synthetic database which combines survey and
administrative data
 Model written in C
 Visual Basic front end released in 2006
8
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
SPSD/M
Public release
1984
1988
Visual SPSM
1992
1996
2000
2004
2008
Michael
Wolfson
Arrives
9
Statistics Canada • Statistique Canada
September 11, 2009
FADEP (Family and Demographic
Projections)

Part of CEPHID (Canada‘s Elderly
Population: Health, Income & Demography)
•



10
Hybrid Static & Dynamic models
Dynamic model of projection of family structure
Closed population
Written in C++
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
SPSD/M
Public release
1984
Michael
Wolfson
Arrives
11
1988
1992
1996
2000
2004
2008
FADEP
Statistics Canada • Statistique Canada
September 11, 2009
POHEM (Population Health Model)




Longitudinal model of health and disease
Cohort model
Comparison of competing health interventions
Multiple versions
• Some use synthetic data and some microdata
 First version written in APL
12
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
SPSD/M
Public release
1984
1988
1992
1996
2000
2004
2008
POHEM
(APL)
Michael
Wolfson
Arrives
13
FADEP
Statistics Canada • Statistique Canada
September 11, 2009
Lessons Learned by 1993





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Dynamic models were hard to maintain and to modify
Coding of models was time consuming and error prone
Flexible/modular design essential
Writing to disk during simulations slows speed
significantly
Closed dynamic models make high demands on
memory and/or have significant sampling variability
Statistics Canada • Statistique Canada
September 11, 2009
Modgen
 Generic tool to create dynamic microsimulation models
 C++ compiler pre-processor
 Features
•
•
•
•
•
•
•
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Event queue
GUI
Derived states
Tables and microdata output (tabulation is on-the-fly)
Continuous or discrete time
Calculating Monte Carlo variability
Multilingual cross-referenced documentation
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
Modgen
SPSD/M
Public release
1984
1988
1992
POHEM
(APL)
Michael
Wolfson
Arrives
16
1996
2000
2004
2008
POHEM
(Modgen)
FADEP
Statistics Canada • Statistique Canada
September 11, 2009
LifePaths
 Dynamic model of individuals and families
designed to analyse government programs
 Overlapping cohort model
 Full cross-sectional population by 1972
 Some of the main research areas: student loans,
pension policy, time allocation, intergenerational
issues
 Written in Modgen
17
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
LifePaths
Modgen
SPSD/M
Public release
1984
1988
1992
POHEM
(APL)
Michael
Wolfson
Arrives
18
1996
2000
2004
2008
POHEM
(Modgen)
FADEP
Statistics Canada • Statistique Canada
September 11, 2009
DEMOSIM (aka PopSIm)
 Demographic projection model
 Projects population by visible minority status
 Starts by reading in the entire 2006 census (20%
of Canada’s population)
 Written in Modgen
19
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
LifePaths
Modgen
SPSD/M
Public release
1984
1988
1992
POHEM
(APL)
Michael
Wolfson
Arrives
20
1996
2000
POHEM
(Modgen)
2004
2008
DEMOSIM
FADEP
Statistics Canada • Statistique Canada
September 11, 2009
CAREMOD
 New model focusing on cost-effectiveness of
cancer treatments and prevention
 Based on POHEM
 Very short turnaround time – contract from
Canadian Partnership Against Cancer
 Part of contract is to put model on the web
• Generic technology being built which can be used for
all Modgen models
21
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
LifePaths
Modgen
SPSD/M
Public release
1984
1988
1992
POHEM
(APL)
Michael
Wolfson
Arrives
22
Caremod
1996
2000
POHEM
(Modgen)
2004
2008
DEMOSIM
FADEP
Statistics Canada • Statistique Canada
September 11, 2009
PERSIM
 Model designed to look at personnel needs for
government departments
 Written in Visual Basic
 Prototype in Modgen created in 2008
 Funding sought to migrate it to Modgen
23
Statistics Canada • Statistique Canada
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
PERSIM
1988
1992
POHEM
(APL)
Michael
Wolfson
Arrives
24
Caremod
Modgen
SPSD/M
Public release
1984
LifePaths
1996
2000
POHEM
(Modgen)
FADEP
Statistics Canada • Statistique Canada
2004
2008
DEMOSIM
PERSIM
Modgen
prototype
September 11, 2009
Major* Microsimulation events at
Statistics Canada
SPSD/M
conceived
PERSIM
1988
1992
25
POHEM
(Modgen)
1996
2000
PopModM
Caremod
RiskPaths
IDMM
POHEM
(APL)
Michael
Wolfson
Arrives
HIVMM
Modgen
SPSD/M
Public release
1984
LifePaths
2004
2008
DEMOSIM
XECON
FADEP
Statistics Canada • Statistique Canada
CVMM
September 11, 2009
Key Issues
Funding
 Different projects have used different funding
mechanisms at different times
 Core funding is available at Statistics Canada
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Statistics Canada • Statistique Canada
September 11, 2009
Main sources of funding
Core
SPSD/M
POHEM
LifePaths
Core funding
critical – clients
unable to
pay full
Funding
Contracts
cost
HRSD X
major
source of
funding
X
X
DEMOSIM
PERSIM
Modgen
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Sales to
clients Pohem
funded
X
creation
X
X
X
GAPS has provided
funding inXrecent
years – ending in
2010
X
Much
development
included in
other projects
X
X
Statistics Canada • Statistique Canada
WHO project
funded
improvements
to interacting
population
CAREMOD
funding
web
interface
September 11, 2009
Who uses the models
 Some models solely used by Statistics Canada
for research at Statistics Canada
 Others are used by the public
 Most models are run by Statistics Canada for
projects funded by external users
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Statistics Canada • Statistique Canada
September 11, 2009
Public availability
Released to
public
SPSD/M
X*
LifePaths
X*
DEMOSIM
Modgen
30
available
X
POHEM
PERSIM
Not yet
CAREMOD
releasedwill be publicly
X*
Only
selected
outputs
Plan to
have public
version of
DEMOSIM
in 2010 –
data may
still be
confidential
X
X
Statistics Canada • Statistique Canada
Personnel
data
confidential
September 11, 2009
Major users
External
users
SPSD/M
X
POHEM
LifePaths
Number of
external
users
increasing
PERSIM
31
Few external
users
X
DEMOSIM
Modgen
Only model
where
Statistics
external
Canada in
users
partnership
represent
majority
with clients
X
Statistics Policy
Canada analysis
not in
mandate
X
X
X
X
X
X
X
X
X
X
X
X
Statistics Canada • Statistique Canada
September 11, 2009
Staffing
 Different groups have used different mix of
personnel throughout the years
 Use of single resource to do the programming
has been a key difference
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Statistics Canada • Statistique Canada
September 11, 2009
Staff mix
One person
programs the
model
SPSD/M
POHEM
Multiple people
program the
model
X
X
LifePaths
DEMOSIM
33
X
X
X
Statistics Canada • Statistique Canada
X
September 11, 2009
10 Lessons gleamed from 25
years of experience
Lesson 1: Have strong leadership
 Michael Wolfson led microsimulation at Statistics
Canada
 Steve Gribble designed SPSD/M and Modgen
 Geoff Rowe spearheaded research and equation
estimation
 All were there from the start in 1984 = 25 years
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 2: Hire and keep the best team
 Takes time to learn microsimulation, best if
personnel can stay for numerous years
 Easier to do if team is big enough to allow for the
possibility of working on new projects
 Multiple projects using the same technologies
makes this much easier to do
 Modgen means that analysts as opposed to
programmers can develop and maintain the
models
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 3: Invest in technology
 Modgen led to rapid development of new models
 Fast creation of prototypes one of the methods
used to develop new markets
 Common language means a more flexible team
 Programming the model should take less time
that analyzing the data that goes into the model
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 4: If it ain’t broke, don’t fix it
 SPSD/M predates Modgen
 Written in C and has had no major overhaul in
>20 years
 Survived:
• Changes in operating systems
• Frequent updates (~2x year)
• External users from across the country
 Visual interface was created 2006
38
Statistics Canada • Statistique Canada
September 11, 2009
Lesson 5: Survive through lean times




39
Policy needs ebb and flow
Core funding important
Diverse client base can cushion the blow
Loyal clients can save the day
Statistics Canada • Statistique Canada
September 11, 2009
Lesson 6: Use “Strategic Opportunism”*
* copyright Steve Gribble
 Technologies like MODGEN makes rapid
prototyping simple
• data analysis takes the time
 Complex models take time to build
 Building on existing models makes sense
• CareMod built on POHEM
• LifePaths used to study pension reform
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 7: Complexity has a cost
 Complex models, like LifePaths, are hard to
keep up to date and have a large overhead
 Can be hard to understand what is causing
change
 Hard to attract users
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 8: Simplicity not always the
answer
 Simple models may not be able to answer the
policy questions of the day
 SPSD/M and Employment Insurance
• SPSD/M has a certain amount of Employment
Insurance history built into it
• Designed at a time when the policy question was
contraction
• Current policy questions have to do with expansion:
model cannot answer these questions
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 9: Links to clients and external
groups essential
 POHEM and SPSD/M, PERSIM and DEMOSIM
team have strong links to external clients
• Some important gaps remain
 LifePaths has struggled on and off through the
years to find significant external interest
 Ties with the microsimulation community of
Ottawa haven’t always been strong
• New seminar series is trying to build a community
• Try to keep people working in microsimulation
modeling
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Statistics Canada • Statistique Canada
September 11, 2009
Lesson 10: Pick good names
 Social Policy Simulation Database and Model
(SPSD/M)
Or in French
 Base de données et modèle de simulation de
politiques sociales (BD/MSPS)
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Statistics Canada • Statistique Canada
September 11, 2009
Thank you!
chantal.hicks@statcan.gc.ca