This paper reports further on the study described in SE 019 717. Correlational data relating success on proportionality tasks to understanding of related concepts and processes are presented. The five correlative tests involve (1) reducing fractions, (2) multiplying fractions, (3) facility with fractions, (4) inverse relations, and (5) more than/times as much. The results of the study suggest that a child's understanding of proportionality is dependent on the task being performed. It is suggested that in teaching proportionality concepts teachers use the simplest possible arithmetic. (SD)