The purpose of this study was to validate the results of cognitive
diagnoses using the rule-space model and to demonstrate the usefulness
of cognitive diagnoses for instruction. The results of the study
strongly indicated that the rule-space model can effectively diagnose
students' knowledge states and can point out ways for remediating their
errors quickly with minimum effort.
It was also found that the designing of instructional units for
remediation can be effectively guided by the rule-space model, because
the determination of all possible ideal item-score patterns, given an
incidence matrix, is based on a tree structure of cognitive attributes,
knowledge states, and items.