1. Introduction

1.1. About LIAM2

LIAM2 is a tool to develop (different kinds of) microsimulation models.

The goal of the project is to let modellers concentrate on what is strictly specific to their model without having to worry about the technical details. This is achieved by providing a generic microsimulation toolbox which is not tied to a particular model. By making it available for free, our hope is to greatly reduce the development costs (in terms of both time and money) of microsimulation models.

The toolbox is made as generic as possible so that it can be used to develop almost any microsimulation model as long as it uses cross-sectional ageing, ie all individuals are simulated at the same time for one period, then for the next period, etc.

1.1.1. License

LIAM2 is licensed under the GNU General Public License (GPL) version 3. This means you can freely use, copy, modify and redistribute this software provided you follow a few conditions. See the license text for details.

1.1.2. Staying informed

You can get notified of new versions and other LIAM2-related announcements by either using our website RSS feed or subscribing to the LIAM2-announce mailing list on Google Groups.

You can do so by entering your email address here:

1.1.3. Credits

The software is primarily being developed at the Federal Planning Bureau (Belgium), with testing and funding by CEPS/INSTEAD (Luxembourg) and IGSS (Luxembourg), and funding from the European Commission. See the credits page for details.

1.2. About microsimulation

Microsimulation is a modelling technique that operates at the level of individual units such as persons, households, vehicles or firms. Each unit has a set of associated attributes – e.g. a person has an associated age, sex, and employment status. In the case of discrete-time dynamic models, a set of rules (intended to represent individual preferences) are applied to these units at each time step, leading to simulated changes in state and possibly behaviour. These rules may be deterministic (probability = 1), such as ageing, or stochastic (probability < 1), such as the chance of dying, marrying, giving birth or moving within a given time period.

The aim of such simulations is to give insight about both the overall aggregate change of some characteristics and, most importantly, the way these changes are distributed in the population that is being modelled. The methodology is often used to design and evaluate public policies that are affected by earlier events and choices as is the case for pensions or education.

1.3. About this guide

This guide will help you develop dynamic microsimulation models using LIAM2. Please note that it describes version 0.12 of LIAM2, but both the software package and this manual are work-in-progress, and are therefore subject to change.