ABSTRACT
Source credibility-ethos, prestige, or image-was originally conceived as a unidimensional attitude a receiver has about a source, but this changed in the mid-1960s when two lines of research began promoting it as a multidimensional attitude. McCroskey’s original scales have been used to confirm that high-and low-credibility speakers are actually perceived in this way and to assess credibility of trial witnesses and immediate superiors in organizations. Little validity evidence for the Likert-type instrument exists. One study tested the construct validity of the Authoritativeness and Character scales and of the Berlo et al. scale; Carbone found that high- and low-credibility sources differed significantly on the two McCroskey dimensions and on the three Berlo et al. dimensions.
