The invariance of anchor points obtained by magnitude estimation and pair-comparison treatment of complete ranks scaling procedures: An empirical comparison and implications for validity of measurement

This article examined the invariance of results from magnitude estimation and pair-comparison treatment of complete ranks scaling procedures and explored whether roughly interval measurement is achieved by these methods. Magnitude estimation and ranking questionnaires were administered to the same set of 116 college students, and their responses were used to scale sets of 20 and 10 frequency expressions, respectively. A comparison of the results obtained with those from two earlier studies indicated that magnitude estimation scaling produced fairly invariant anchor points which appear to attain at least roughly equal interval measurement, whereas pair-comparison treatment of complete ranks did not. Implications for validity of measurement are briefly discussed.