LIAM 2: a new open source development tool for the development of discrete-time dynamic microsimulation models

, " Towards the development of a dynamic Microsimulation toolbox « LIAM-II » and the complementary implementation of administrative Data needed for dynamic microsimulation of pensions in Luxembourg ". The authors gratefully acknowledge the support of the European Community Summary: Most existing microsimulation models have been developed by separate (teams of) researchers. The drawback of each team working on its own is that they have to put a lot of time and effort in the customary development of fairly general simulation tools. Hence, economies of scale cannot be exploited, which makes microsimulation models even more expensive than strictly necessary. Furthermore, as modellers often are not professional programmers, the result is not necessarily the most efficient in terms of simulation speed. The objective of this paper is to introduce and present the simulation modelling package LIAM2. This is a free, open source, user-friendly modelling framework, designed for the development of discrete-time dynamic models with cross-sectional dynamic ageing and making profit from state-of-the-art methods for data-handling and simulation optimization. The paper presents a very rudimentary model and discusses the performance of LIAM2 in terms of data capacity and simulation speed. Though the latter could (and might) be better, the capacity of LIAM2 to handle large datasets is quite good, seeing that the current version of the Belgian MIDAS model simulates a dataset of no less than 2.2 million individuals.