The use of measures and scales without due attention to their reliabihty and validity is one of the major factors contributing to the mass of equivocal fmdings in marketing research. As has been pointed out, if unequivocal results are to emerge, marketing researchers must develop and design their own instruments to measure reliably and validly the particular concepts being investigated (Jacoby 1978; Kassarjian 1971). To this end, a scale to measure self-concepts, person concepts, and product concepts is developed. Measurements of such concepts are required in a variety of marketing research situations. The objective here is to describe the construction of the scale rather than to present a generalized scale for measuring self-concepts, person concepts, and product concepts. This description should enable other researchers to develop their own scales to suit specific problems. The specific concepts chosen for the study are automobiles and actors. The steps in the scale development procedure are summarized in Figure 1. The theoretical foundations, initial item selection, item analyses, and assessment of reliabiUty and validity of the scale are described.