Abstract
Engineering design is a complex multifaceted and knowledge-intensive process. No single theory or model can capture all aspects of such an activity. Various empirical methods have been used by researchers to study particular aspects of design thinking and cognition, design processes, design artefacts, and design strategies. Research methods include think-aloud protocol analysis and its many variants, case studies, controlled experiments of design cognition, and fMRI. The field has gradually progressed from subjective to objective analyses, requiring well-defined metrics since design of experiments (DOE) involves controlling or blocking particular variables. DOE also requires setting experiment variables at particular levels, which means that each variable needs to be characterized and quantified. Without such quantification, statistical analyses cannot be carried out. This chapter focuses on quantifiable characteristics of designers, targeted users, artefacts, and processes.