A continuity principle is suggested for scaling of assessment scores from different levels of a multilevel mastery training program. In such training programs students are self-paced and work at levels of tasks appropriate for their levels of performance. The problem addressed in this report concerns the scaling of assessment scores at different levels so as to form a single basic scale. The solution proposed here involves relative scalings of the scores at different levels so that the mean converted score over all students forms a smooth, continuous curve. The smoothness of this mean curve is measured by higher order differences between consecutive scores. Computational procedures to obtain as smooth a curve as possible are presented. (Contains 11 tables, 9 figures, technical notes, and 1 reference.) (Author)