June 22, 2017

The Code is the Model

Today, I am going to present a paper titled ‘The Code is the Model’ at the World Congress of Microsimulation. Feel free to download the current draft and let me know what you think.

Illustration of the Modeling Process Abstract: Conventionally, agent-based models are specified in a combination of natural language and mathematical terms, and their implementation seen as an afterthought. I challenge this view and argue that it is the source code that represents the model best, with natural language and mathematical descriptions serving as documentation. This modeling paradigm is inspired by agile software development and adopting it leads to various - mostly beneficial - consequences. First, discrepancies between the specification documents and what the model actually does are eliminated by definition as the code becomes the specification. Second, replicability is greatly improved. Third, object-oriented programming is recognized as an integral part of a modeler’s skill set. Forth, tools and methods from software engineering can support the modeling process, making it more agile. Fifth, increased modularity allows to better manage complexity and enables the collaborative construction of large models. Sixth, the way models are published needs to be reconsidered, with source code ideally being part of the peer review. Seventh, the quality of source code in science is improved as it enjoys more importance, attention and scrutiny

“In using systems of adaptive agents to create a ’guess’, we are counting on the tendencies of these systems of adaptive agents, as plodding as they are, eventually to find their ways to equilibria that we economists (who, after all, made up the model!) have difficulty finding.”
Thomas Sargent in 'Bounded Rationality in Macroeconomics'