Workshop Synthesis: New directions in experimental design

This paper summarizes the discussion of the workshop “new directions in experimental design”, in which the evolution of experimental designs was discussed in the context of the rapid changes and challenges that the transportation field is experiencing. Because an experimental setting in travel behavior analysis is associated with stated preference methods, the workshop had a clear focus on the design of discrete choice experiments. However, one of the main conclusions is that we need an expanded notion of experiments to achieve diversity in the participation of experimentalists beyond standard stated preference analysts. In this broader, more holistic definition of experiment, workshop participants made clear that good designs need to explicitly address treatments and control, as well as the identification of a good, appropriate baseline for valid hypothesis testing. In fact, the group also discussed the idea of “experiment design of the experiment design” meaning that we should control in a methodical way the parameters of the design so that analysts can assess and formalize design protocols, while also examining the combined use of conventional and new tools.