The report is a review of research results which concern sequencing (procedures for validating the hypothesized ordering of the subordinate tasks in a learning hierarchy) and practical applications of learning hierarchies in instructional design. Indirect versus direct validation procedures are examined in detail. (Author)

Three methods of sequencing coordinate concepts (simultaneous, collective, and successive) were investigated with a Bayesian, computer-based, adaptive control system. The data analysis showed that when coordinate concepts are taught simultaneously (contextually similar concepts presented at the same time), student performance is superior to either…