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News

PS-I

An Agent-Based Modeling Simulation Toolkit

Over the last four years we have developed a "user-friendly" computational modeling platform known as PS-I (standing, originally, for "Political Science--Identity"). Researchers using models produced with this toolkit need not be computer programmers. Our intent is to make available to political scientists and other social scientists (with no programming skills and no previous background in formal modeling) readily accessible agent-based modeling tools for exploiting islands of good theory to address and productively analyze political phenomena.

In 2002 Lustick and the PS-I project were awarded a three year grant from the National Science Foundation entitled: "Development and Applications of the PS-I Computational Modeling Platform for Problems of Ethnic Conflict, Globalization, State Stability, and Terrorism." Work under the grant is directed toward improving and expanding the quality of agent-based simulations for problems in the social sciences, with special emphasis on political science. Our interest is in drawing on this methodology to investigate problems located on disciplinary frontiers, including problems considered intractable for theoretical or empirical reasons. We also have a strong commitment to developing applications of agent-based modeling for various public policy problems.

In addition to pursuing specific research questions, our project seeks to anchor the design of simulations in the assumptions and propositions of pre-existing theories. We are building interfaces that allow end-users to refine simulations in iterative processes of experimentation without having to become computer programmers to do so. We our particularly interested in outreach to scholars whose methodological preferences or substantive areas of interest have not led them to explore the possible usefulness of agent-based modeling techniques for improving their research and deepening their insights.

So far, the project has enabled participants to present their work at a wide variety of scholarly conferences and includes establishment of a cross-disciplinary workshop, sponsorship of a variety of training opportunities, graduate student and post-doctoral support, research assistantships, and regular graduate and undergraduate course offerings.

A note on "PS-I" and "ABIR"

When Lustick and Dergachev first developed an agent-based model in 1998, they did so for the purpose of experimenting with and refining propositions derived from constructivist identity theory. Through many iterations they produced a set of agent types, micro-rules, landscape options, and other distinct capabilities. As their work with this model proceeded, emphasizing the implications of variation in the characteristics of landscape heterogeneity and agent-repertoire size and landscape complexion, Lustick and Miodownik named the model "ABIR," the Agent-Based Identity Repertoire model. ABIR (and ABAR—for Agent-Based Argument Repertoire) was the term used by Lustick and Miodownik until 2002.

As demands for flexibility increased in response to the widening scope of our investigations, Dergachev began work on an elegant and systematically arrayed set of modeling capabilities for agent-based simulations. The objective was a platform or toolkit for non-programmers that would be presented in a user-friendly fashion and that would bind the user to as few assumptions about the behavior of agents, rules for their transformation, or the nature of their environments as possible. Dergachev dubbed the overall project PS-I, standing, in his mind, for "Political Science--Identity." The label stuck, but in some quarters the ABIR meme had already taken hold.