1. LIAM 2: A NEW OPEN SOURCE DEVELOPMENT TOOL FOR THE DEVELOPMENT OF DISCRETE-TIME DYNAMIC MICROSIMULATION MODELS GAËTAN DE MENTEN (Federal Planning Bureau) GIJS DEKKERS (Federal Planning Bureau, CESO University of Leuven, and CEPS/INSTEAD) PHILIPPE LIÉGEOIS (CEPS/INSTEAD and DULBEA, ULB) RAPHAËL DESMET (Federal Planning Bureau) RAYMOND WAGENER (IGSS) CATHAL ODONOGHUE (TEAGASC and NUIR) IGSS Luxembourg

2. 2 C ONTENTS OF THE P RESENTATION LIAM2 : Objectives Situating LIAM2 in the family of modelling packages Some key elements of LIAM2 PERFORMANCE of LIAM2 Conclusions LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

3. 3 Microsimulation models simulate compound objects, such as holdings/firms/plants; groups/households/individuals) on a moment in time, or their events over time. In a dynamic setting, individuals are born (firms are started), they marry/divorce (firms merge, parts are sold), go through an economic career (idem), they retire and die (go bankrupt; are absorbed by another firm). All these processes can be modelled and simulated by LIAM2 G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012 LIAM2 IGSS Luxembourg M ICROSIMULATION

4. 4 I NTRODUCTION LIAM2 is a new tool for the development of (large scale) dynamic microsimulation models (prospective as well as retrospective) with dynamic cross-sectional ageing (but also static models as a by-product) The result of a collaborative project Development and testing: Federal Planning Bureau Testing and complementary funding: CEPS/INSTEAD and the General Inspectorate of Social Security (IGSS) in Luxembourg LIAM and conceptual assistance: Cathal ODonoghue European funding (MiDaL Project 2009-2011, PROGRESS programme, Grant VS/2009/0569) LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

5. 5 LIAM2 : O BJECTIVES LIAM2 IGSS Luxembourg A development framework for the modelling and simulation of large scale discrete-time dynamic microsimulation models with cross-sectional dynamic ageing and alignment A user-friendly and efficient development framework : Separate modellers and programmers Implementation of language which is easy to use for the modellers Use state-of-the-art methods for data handling and simulation Stimulate collaboration between development teams through the use of a common development approach Be open source, so that developers worldwide may add to the toolbox and make accessible their own modules when relevant for the community G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

6. 6 S ITUATING LIAM2 Developed based on the experience gained through using LIAM, but more general, faster, higher capacity, YAML, user interaction, modeling on multiple object levels, etc. GENESIS : a generic SAS model and dataset. JAMSIM, ModGen : libraries for microsimulation in Java, respectively C++. GENESIS used only by the UK MW&P. Not available ModGen, JAMSIM : Available but not open source LIAM : Available and open source ad hoc on request LIAM2: Available and open source (GNU Public License version 3) LIAM2; GENESIS = discrete-time dynamic ageing MSM JAMSIM = discrete-time agent-based (?) models, ModGen = (mostly) continuous-time modelling. LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

7. 7 A M ODEL IN LIAM2 : (A) T HE B RICKS ENTITIES : objects (persons, households, firms, cell, …) with a unique identifier FIELDS : attributes of an entity (e.g. persons age) LINKS : relation between entities (e.g. persons children) ; can lead to subsequent use (e.g. spouse.mother.age) GLOBALS : a parameter not related to a specific entity, may vary through time (e.g. CPI) PROCESSES : assignments, which change the value of a variable (e.g. « age+1 ») using an expression, and actions which do not (e.g. remove dead person) MACROS : piece of code, re-evaluated each time it is referenced (e.g. « WIDOW: civilstate == 5 ») LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

8. 8 A M ODEL IN LIAM2 : (B) P REPARING THE I NPUT D ATASET One CSV file for « globals » and one file for all entities and fields Create a description file, then run it (e.g. bundled editor, F5) => HDF5 Input created « normal.h5 » NB : This creation must be done only once (then LIAM2 reads the HDF5 input as it has been set earlier) LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

9. 9 A M ODEL IN LIAM2 : (C) THE GENERAL STRUCTURE LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

10. 10 A M ODEL IN LIAM2 : (C) D EFINING – A DDITIONAL F EATURES LIAM2 allows for « many2one » or « one2many » links mathematical functions, conditional expressions, aggregate functions, temporal functions, link functions, random functions, stochastic simulations, life-cycle functions, matching functions, output functions LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

11. 11 « logit_regr(expr[, align=filename)]) » No specific routine for monetary alignment is needed. LIAM2 allows for state alignment by sorting on –up to- 3 dimensions at a time. E.g. alignment to gender, age-category and previous labour market state. LIAM2 allows for « soft » and « hard » take- and leave- routines Soft take and leave: manipulate the risks Hard take and leave: specify categories within the alignment procedure A M ODEL IN LIAM2 : A WORD ON ALIGNMENT LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

12. 12 A M ODEL IN LIAM2 : (D) R UNNING AND (E) D EBUGGING & O UTPUTTING Run the model (e.g. bundled Notepad++ editor => F6) Debugging e.g. through interactive console while running (error messages or intermediate results) or at the end or ex post Breakpoints (« breakpoint([period]) ») can be introduced in the model, which will automatically launch the interactive console LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

13. 13 PERFORMANCE of LIAM2 LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

14. 14 T HE STATE OF AFFAIRS : WHERE IS LIAM 2 BEING USED ? The model MIDAS_BE is operational in Belgium Model developments are being done in Luxembourg (CEPS/INSTEAD: MIDAS_Lu), Hungary (CANPI: MIDAS_Hu), Italy (Tesoro: T-DYMM) Testing is going on in the Netherlands (Uitvoeringsinstituut Werknemersverzekeringen) UK (Department of Work and Pensions) Academics in Japan, South Korea, Suriname, the Netherlands, Spain LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

15. 15 LIAM2 : HOW TO PROCEED? Download the LIAM2 bundle from http://liam2.plan.be/http://liam2.plan.be/ The bundle includes : The executable (either 32 or 64 bit version) A text editor (Notepad++), pre-configured to work with LIAM2 Documentation A demonstration model (20,200 persons, 14,700 households) Create the starting dataset, alignment tables and behavioural equations have fun! LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

16. 16 C ONCLUSIONS LIAM2, a new development tool for the development of (large scale) static and discrete-time dynamic microsimulation models User-friendly and Open source (low entry cost) Efficient and fast, using state-of-the-art methods for data- handling and simulation methods, transparant for the end- user (modeller), using YAML and macros. Available for free LIAM2 IGSS Luxembourg G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012

17. 17 T HANK YOU – M ERCI BIEN LIAM2 G IJS D EKKERS - S ÉMINAIRE SCIENTIFIQUE C AISSE DES D ÉPÔTS, B ORDEAUX L AC. J EUDI 15 NOVEMBRE 2012 IGSS Luxembourg