Since the days of Corax and Tisias rhetorical theorists have been concerned with the role of ethos in communication. 1 In recent years ethos, sometimes referred to as credibility or prestige, has been a frequent variable for study or control in experimental research in speech, psychology, sociology, and education. 2 In many of the early studies differences in ethos levels were assumed. In more recent studies the ethos level has usually been measured. The methods of measuring ethos levels have included rankings, sodograms," prestige indexes," linear rating scales, Thurstone-type attitude scales, and devices similar to Likert scaling techniques, including the semantic differential. 3

Construction and scoring of attitude scales like those just mentioned is time consuming, but by using Likert scales and the resources of modern computers much time can be saved. The usual fivechoice, strongly-agree to strongly-disagree Likert scale lends itself to machine scoring. Subjects may indicate their responses to scale items on standard IBM answer sheets. The answer sheets can be run through a Digitex scoring machine which will punch the subject's responses on IBM cards so a computer may be used for actual scoring.