The general emphasis of Project LONGSTEP was on the identification of changes in student achievement that occur as a result of intensive educational innovation. This report focuses on three groups of students: those who started out as first-graders, fourth-graders, and sixth-graders in 1970-71. Its primary purpose was to analyze overall differences in achievement growth among educational approaches; an educational growth model in which achievement was related to innovative emphasis, number of minutes of instruction per day, pretest, socioeconomic status, and teaching qualifications; a posttest achievement score statistically adjusted for pretest and socioeconomic differences; groups of students with similar educational experiences who, on the average, performed either much better or much worse than was expected from their pretest and socioeconomic status; and students who demonstrated particularly large achievement gains during two consecutive school years. Even though overall project findings showed that dramatic school effects were not associated with intensity of educational innovation, different educational approaches did produce meaningful and important differences in achievement, especially in the early elementary grades. Unquestionably large gains in reading, language, and arithmetic skills, over and above those expected on the basis of pretest and socioeconomic status, were found to occur in some of the participating schools. "Data Collection Instruments and Guidelines" developed for Project LONGSTEP referenced in Vol. I, Chapter II, Section C, will be accessioned TM 005 987 in RIEMAY77. (RC)