When a group of school districts, such as those that make up the schools of the State of California, adopts a new arithmetic series, there arises almost immediately a need for every conceivable type of analysis and information that will make the transition from the old to the new a smooth and enlightened one. How will use of the new series affect the pupil scores on the regularly given standardized tests? What percent of mastery of material presented at each grade level in the new series will be required to be "at grade" according to the standardized tests? Which standardized test will best evaluate student progress in the new series? These are questions that good teachers and alert public relations conscious school systems will want answers for as use of the series begins. lt is hoped that this study will in part help in the interpretation of these questions and others similar to them, and thereby indirectly make the newly adopted California Arithmetic Series a more effective medium for the education of California's children.