Presented are variables and conditions for design of a computer-based adaptive instructional system. The design strategy uses Bayes' theory of conditional probability to determine an instructional sequence according to individual student characteristics and needs. The adaptive strategy uses prior estimates based on student pretask and on-task performance in an algorithm that makes selections of instructional sequence from a table of generated values. The computer system provides a dynamic environment which updates each students on-task learning progress and modifies the instructional sequence accordingly. The purpose of this adaptive strategy is to improve the effectiveness of the learning environment, resulting in reductions in student learning time while improving task acquisition.