Introduction

We focus in this chapter on explaining the processes used in generating an experimental design, although we warn that the reader will not become an expert after having completed this chapter. Like choice modeling, experimental design is very much owned by the specialist. We have decided to concentrate on the practical aspect of experimental design, as conversations with both colleagues and students over many years have confirmed that it is perhaps this topic which is the least understood subject matter related to choice modeling. We refer those readers interested in the theoretical aspects of experimental design to other texts such as Louviere, Hensher, and Swait (2000) which provide a more detailed treatment of the topic.

If at the end of this chapter the reader can understand the jargon used in the experimental design literature and generate simple experimental designs then we will be satisfied that we have achieved our aim.

What is an experimental design?

The foundation for any SP experiment is an experimental design. An experiment defined in scientific terms involves the observation of the effect upon one variable, a response variable, given the manipulation of the levels of one or more other variables. The manipulation of the levels of the variables does not occur in a haphazard manner. Rather we turn to a specialized form of statistics to determine what manipulations to make and when to make them. Thus we can say that the manipulations occur by design.