ABSTRACT
In the method of equal-appearing intervals, as originally described by Thurstone and Chave, each statement concerning the psychological object of interest is printed on a separate card and subjects are then asked to sort the statements on the cards into a number of intervals. Along with the cards containing the statements, each subject is given a set of 11 cards on which the letters A to K appear. The 11-point scale then becomes the psychological continuum on which the statements have been judged and all that is required is that some typical value be found for the distribution of judgments obtained for each statement. By placing tracing paper over the chart, the cumulative proportion graphs for the individual statements could be quickly drawn and the scale values and 75th and 25th centiles readily found. The attitude score is based upon the arithmetic mean or median of the scale values of the statements agreed with.
