The art of building dynamic systems models

In this chapter we aim to provide the reader with guidelines to build one's own quantitative dynamic systems model. To be able to build such a model, two types of knowledge are important. The first type concerns the knowledge of how to translate theoretical notions into a conceptual dynamic systems model, and how to translate that conceptual model into quantitative expressions. The chapter will focus on this first type of knowledge. The second type of knowledge concerns the technical part - knowledge about which software to use, the type of equations that represent different types of development, etc. In addition, knowledge is needed about how to enter quantitative mathematical expressions in a spreadsheet, how to generate simulations and how to make graphs. In our examples and explanations we use spreadsheets, because our aim is to make the art of model building available for all colleagues, not only for those highly skilled in computer programs and mathematics. Spreadsheet programs have proved to be very useful for building dynamic systems, and most people have these programs. So, in this chapter we will describe the process from general theories to a quantitative dynamic systems model. We will do that by means of an example: the building of a model of commitment development. The chapter will describe the modeling process in different steps.