ABSTRACT
The choice of measurement instrument is a critical component of any research undertaking in the behavioral sciences and is a topic that has spawned theoretical development and debate virtually since the dawn of our fi eld. Unlike the eminently observable subjects of many other fi elds of scientifi c inquiry-for example, the physical characteristics of rock cores in sedimentary stratigraphy or the velocity of blood fl ows in biomedical engineering-the subject of interest in behavioral research is often human thoughts, feelings, preferences, or cognitive abilities that are not readily apparent to the investigator, and which may even be out of the full awareness of the research participant. Over the years, many hundreds of tools, such as pencil-and-paper questionnaires, projective tests, neuropsychological batteries, and, more recently, electrophysiological and neuroimaging techniques, have been developed or tailored in an attempt to capture the essence of various behavioral phenomena. For the research (or indeed, applied) behavioral scientist, the question arises: When it is time to operationalize a behavioral construct of interest, how should I choose and implement an instrument in a way that is consistent with ethical practice?
