Simulation as a method
This chapter is about the use of computer simulation as a method of social research: the logic behind the method, the stages that one needs to go through and the pitfalls to be avoided. To start, we need to define some terms.
We shall assume that there is some ‘real world’ phenomenon which you, the researcher, are interested in. This we call the target (Doran and Gilbert 1994; Zeigler 1985). The aim is to create a model of this target that is simpler to study than the target itself. We hope that conclusions drawn about the model will also apply to the target because the two are sufficiently similar. However, since our modelling abilities are limited, the model will always be simpler than the target. For example, we might model the real market for the wholesale supply of fish with a simpler system where both suppliers and purchasers are represented by computer programs standing in for complex and multifaceted businesses and their customers (cf. Weisbuch et al. 1997).
In the social sciences, the target is always a dynamic entity, changing over time and reacting to its environment. It has both structure and behaviour. This means that the model must also be dynamic. We can represent the model itself as a specification – a mathematical equation, a logical statement or a computer program – but to learn something from the specification, we need to examine how the behaviour of the model develops over time. One way of doing this is using an analytical method. This entails deriving the model’s future structure from the specification by reasoning, perhaps using logic or more often by using mathematics. For example, we might have a model of the relationships between a set of macroeconomic variables and use algebra to derive the outcome if one of those variables changes over