Summary.Three important deficiencies of learning hierarchy validation studies—inadequate scope, inappropriate validation technique and lack of replicative data—were identified, and substantially resolved in the construction and replicate validation of a comprehensive network of graphical interpretation skills. The two parallel validation studies involved 204 grade 8 students in Queensland and 212 grade 8 students in South Australia, both groups containing approximately equal numbers of male and female students. The results in both validation studies were relatively consistent, substantiating the postulated learning hierarchy and thus providing further supportive evidence for Gagné's model of hierarchical lear