A variety of activities, from writing term papers to building nuclear power plants, have very similar dynamic characteristics. These projects have an initial goal, a lot of work towards the goal, and more or less successful completion of the goal. Projects often fail to achieve the expected goal, and cost overruns, time overruns, and poor quality, are common.
In this chapter, we will develop a model to help understand the processes involved in getting a project done. This project model focuses on the design of a new building, although the model is directly applicable to other activities such as designing a new product, preparing a presentation, developing software, or building a space shuttle.
In conceptualizing and creating this model, we will use an iterative approach. We will start with the simplest structure that is relevant to this problem, and continually refine it. The iterative technique is useful because it prevents a situation in which you have completed a large, complex model, but the simulation results do not make sense. You will be simulating at every step, and seeing the effects of new model structure as it is added.
In developing this model, we will be depending on the computer to continually give us feedback on the consequences of changing structure. While the computer is good at this, it is also important to think about what we are doing. Before any simulation experiment is run you should ask yourself what you expect the results to be. If you are surprised, find out why. If you are right, make sure it is for the right reasons. To keep yourself honest, it is helpful to write down predictions about each run beforehand; many experienced modelers keep a notebook documenting model changes, surprising behavior, and important insights as they work.