This document presents information on one school district's approach to the introduction of success-based instruction. The first section defines success-based instruction, also called "predictable learner mastery" (PLM) and the requirements for having an operational system. The second section compares mastery learning with the PLM system adopted by the district. The third section presents information on the scores the district's students obtained on two standardized tests and data on staff development related to the new system. The final section presents a chart that outlines the events that influenced the adoption of the program and gives some detail on key events centering on the board of education and the teachers. (IRT)