This paper is the first-year report of a three-year project in Edina, Minnesota, developing a system for measuring differences among classroom environments and organizational patterns. Dimensions measured include teacher preferences for classroom structure, student perceptions of learning environments and classmate behavior, student attitudes, classroom activities, teacher student interaction, and parent attitudes toward learning environments. The study compares four alternative, elementary classroom organizational patterns: semidepartmentalized, multiaged, nongraded team, open alternative, and self-contained classroom. One purpose of this evaluation is to assist program developers by providing them with descriptive data about classroom environmental characteristics. The long-range goal of the three-year study is to establish a basis for future assessment of the correlates of student achievement in alternative learning environments. (Author/DS)