ABSTRACT
Quantitative research in every branch of psychology involves the measurement of psychological constructs, and consumer psychology is no exception. The use of psychometrics has allowed consumer psychologists to gain insights into the nature of consumers and their behaviour that could not be uncovered by any other means as accurately or effectively. While the psychometric approach within this area has received criticism—most famously from proponents of the C-OAR-SE method—it remains the dominant model for scale development within the field.
This chapter outlines the use of psychometrics within consumer psychology and related fields—both in academic and practice settings—and discusses the theoretical underpinnings of psychological measurement in the form of Classical Test Theory and Item Response Theory. The chapter goes on to discuss in detail the process that psychologists use to design and develop these measures, offering a step-by-step introductory guide to the best practice approach that can be taken to development of a psychometric measure. While the inductive approach is discussed, the chapter focuses on the deductive approach to scale design. The chapter details the processes of item generation, examination of content validity, scale development, establishment of reliability and validity, and standardisation and norming of the final tool.
