Equal-appearing interval scale values and successive interval scale values derived from the same set of ratings.

Abstract

Both equal-appearing interval scale values and successive interval scale values were computed for each of five sets of ratings on five different kinds of stimuli. The scale values obtained by these two methods rank ordered almost identically the stimuli which were scaled. For all five sets of ratings, the Pearson r for estimating the relationship between the two sets of scale values was equal to or greater than .99. In view of the close relationship between the scale values derived by the two methods, practical considerations would make the method of equal-appearing intervals the preferable one for many purposes.