GAËTAN DE MENTEN ( Federal Planning Bureau)

1. IGSS Luxembourg 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 O’DONOGHUE (TEAGASC and NUIR)

2. LIAM2 Contents of the Presentation IGSS Luxembourg LIAM2 : Objectives Situating LIAM2 in the family of modelling packages Some key elements of LIAM2 PERFORMANCE of LIAM2 Conclusions Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

3. LIAM2 Microsimulation IGSS Luxembourg 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 Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

4. LIAM2 Introduction IGSS Luxembourg 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 O’Donoghue European funding (MiDaL Project 2009-2011, PROGRESS programme, Grant VS/2009/0569) Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

5. 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 LIAM2 LIAM2 : Objectives IGSS Luxembourg Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

6. LIAM2 Situating LIAM2 IGSS Luxembourg Developed based on the experience gained throughusingLIAM, but more general, faster, highercapacity, YAML, user interaction, modeling on multiple objectlevels, 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 availableModGen, 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. Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

7. LIAM2 A Model in LIAM2 : (A) The Bricks IGSS Luxembourg ENTITIES : objects (persons, households, firms, cell, …) with a unique identifier FIELDS : attributes of an entity (e.g. person’sage) LINKS : relationbetweenentities (e.g. person’schildren) ; canlead 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-evaluatedeach time itisreferenced (e.g. « WIDOW: civilstate == 5 ») Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

8. LIAM2 A Model in LIAM2 : (B) Preparing the Input Dataset IGSS Luxembourg One CSV file for « globals » and one file for all entities and fields Create a description file, thenrunit (e.g. bundled editor, F5) => HDF5 Input created «normal.h5 » NB : This creationmust bedoneonly once(then LIAM2 readsthe HDF5 input as it has been setearlier) Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

9. LIAM2 A Model in LIAM2 : (C) the general structure IGSS Luxembourg Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

10. LIAM2 A Model in LIAM2 : (C) Defining – Additional Features IGSS Luxembourg LIAM2 allows for • « many2one » or « one2many » links • mathematicalfunctions, • conditional expressions, • aggregatefunctions, • temporal functions, • linkfunctions, • randomfunctions, • stochastic simulations, • life-cycle functions, • matchingfunctions, • output functions Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

11. LIAM2 A Model in LIAM2 : a word on alignment IGSS Luxembourg « logit_regr(expr[, align=‘filename’)]) » No specific routine for monetaryalignmentisneeded. 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: specifycategorieswithin the alignmentprocedure Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

12. LIAM2 A Model in LIAM2 : (D) Running and (E) Debugging & Outputting IGSS Luxembourg Run the model (e.g. bundled Notepad++ editor => F6) Debugginge.g. throughinteractive console • while running (error messages or intermediateresults) • or at the end • or ex post Breakpoints (« breakpoint([period]) ») canbeintroduced in the model, whichwillautomaticallylaunch the interactive console Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

13. LIAM2 PERFORMANCE of LIAM2 IGSS Luxembourg Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

14. LIAM2 The state of affairs: where is liam2 being used? IGSS Luxembourg The model MIDAS_BE is operational in Belgium Model developments are beingdone in • Luxembourg (CEPS/INSTEAD: MIDAS_Lu), • Hungary (CANPI: MIDAS_Hu), • Italy (Tesoro: T-DYMM) Testingisgoing on in • the Netherlands (UitvoeringsinstituutWerknemersverzekeringen) • UK (Department of Work and Pensions) • Academics in Japan, South Korea, Suriname, the Netherlands, Spain Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

15. LIAM2 LIAM2 : HOW TO PROCEED? IGSS Luxembourg Download the LIAM2 bundle fromhttp://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! Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

16. LIAM2 Conclusions IGSS Luxembourg LIAM2, a new developmenttoolfor 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 Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012

17. LIAM2 Thank you – Merci bien IGSS Luxembourg Gijs Dekkers- Séminaire scientifique Caisse des Dépôts, Bordeaux Lac. Jeudi 15 novembre 2012