In the present study the use of the law of comparative judgement is generalized to the successive intervals and graphic rating scale methods. A procedure for calculating the modal discriminal process and discriminal dispersion of the stimuli, as well as the values of any selected point on the continuum, is given. From the estimated values it is possible to determine the theoretical proportions and to compare them with the actual experimental proportions. The agreement between these values is an indication of the adequacy of the assumptions made in the development of the procedures described. The experimental results indicate that the procedure followed in this paper gives an accurate reproduction of the actual values.