Personalized System of Instruction

Stress on the Written Word

Communication between the teacher and the learner is by written word, usually the standard textbook, computer-generated documents or Web sites developed by the instructor. Many distance learning courses are designed in a similar fashion; PSI is an ideal format for offering a web-based course. The PSI instructor prepares detailed study guides by listing all of the learning objectives for a reading assignment. For example,

Many PSI study guides contain study questions that follow along with the text, prompting active responses, instead of learning objectives.

Unit-Perfection Requirement for Advancement

PSI instructors divide the content of their courses into one to two subdivisions or “units” for each week of the course. Once instructors outline a unit sequence, they develop three to four parallel versions of quizzes for each unit. Unit quizzes usually contain multiple-choice and short-answer essay questions and typically take 10 to 20 minutes to complete. Students take tests on each unit as many times as necessary until they reach “mastery,” which is generally defined as 90% correct. Students are not penalized for errors. As Sherman often said, we judge our art masterpieces not by the number of preliminary sketches discarded along the way, but by the final product produced. Once students achieve a mastery score on a unit quiz, they proceed to the next unit.

In traditional classrooms where mastery is not the goal, time to learn objectives or a module or topic is held constant and, as a result, quality of learning varies. Both time and quality cannot be held constant. At the end of a time period, a teacher may test students' competencies, or projects may serve as evidence of progress. Progress will vary from the most to least “capable” learners. In contrast, in PSI, quality of learning is held constant and time is allowed to vary. As with other mastery learning approaches of the 1960s and 1970s, PSI advocates argue that the aspect of teaching that should vary is “time to completion” of a course of study, not “quality of learning.” The mastery philosophy of learning recognizes that individual differences exist among students and that these differences are reflected in the learning process. Some learners may need extra test opportunities for a variety of reasons, including learning challenges, family circumstances, and other demands on their lives and times. But these differences are more adequately described by differences in rate of learning, not by the final level of learning achieved.

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