Introducing the comparative open-source model microWELT
This tutorial introduces the microWELT model and modular modelling platform for comparative dynamic microsimulation. MicroWELT is a portable, continuous time interacting population model built to work with readily available data for many countries, and it supports optional alignment to aggregate targets. It is “X-compatible”: the same model code can be compiled using Modgen or the open-source openM++ environment. As documented on the project website www.microWELT.eu, the model is also extendable to refined national applications such as the microDEMS model, which applies the same platform to an Austrian setting using detailed longitudinal administrative records, illustrating how the shared core can be refined when richer data are available.
Participants will learn (i) the conceptual architecture of microWELT as an interacting population model (entities, states, events, and exposures in continuous time); (ii) the platform’s modular structure and (iii) how to use the documentation and web resources to adapt the platform to new research questions. We will show examples of comparative and national applications developed in different research contexts. The emphasis is on “how to get started”: using microWELT as a reference implementation, a starting template for new applications, and a training resource for dynamic microsimulation workflows. We will also point participants to the platform’s step-by-step implementation material, organised to introduce core concepts first and usable as a textbook-style reference when extending models.
MicroWELT lowers the barrier to comparative analysis by providing a shared, well-documented model core that can be reused across countries and projects. Its continuous-time framework is well suited to life-course processes and interacting individuals (e.g., partnership formation and dissolution), while its modularity allows users to extend the core demography to topics such as education, labour force projections, health, long-term care, pensions and other policy-relevant outcomes. Because aggregate outcomes can be aligned to official projections, users can combine micro-level heterogeneity with macro-level consistency - useful when communicating scenarios to policy audiences and when comparing results across countries. Cross-compatibility with Modgen/openM++ also supports both “production-style” workflows and reproducible open-source deployment.
Our team brings 25 years of experience developing dynamic microsimulation models with the Modgen/openM++ programming technology and pioneering comparative, cross-national models. MicroWELT is implemented at the Austrian Institute of Economic Research (WIFO), and our work spans model architecture, parameterization, implementation, documentation, and applied comparative studies.
The tutorial is aimed at applied researchers, graduate students, and policy analysts who want a concrete, working example of a comparative continuous-time dynamic microsimulation platform and guidance on how to build their own applications. For participants not familiar with Modgen/openM++, we recommend also attending the companion tutorial led by Doug Manuel introducing openM++ and the repository stcOpenMpp.