In the last few chapters, and particularly in Chapters 6 to 8, we have described a very empirical approach to solving problems. We have concentrated on an approach to problem solving that involves you in collecting and analysing data obtained from the real world. As we mentioned in Chapter 6, it may be that your institution will require you to take this approach to your dissertation. However, there are other approaches to problem solving that you might consider, other than straightforward statistical analysis of real data. In this chapter we will discuss these other approaches, as well as discussing more widely the role of modelling in your dissertation.