This study compares an open space elementary school and a traditional school in Harford County, Maryland, in terms of cognitive and non-cognitive student outcomes. In order to assess whether there were differences in instructional climate (open vs. traditional) between the two schools, the Walberg and Thomas Teacher Questionnaire was administered to 27 teachers in the open school and 20 teachers in the traditional (control) school as an index of the teachers' opinions and practices. The results supported anticipated differences in instructional climate between the open and control schools. The subjects of the study were 127 third grade students (65 open, 62 control) and 139 fifth grade students (81 open, 58 control). The subjects were tested on achievement (the Iowa Tests of Basic Skills) and abstracts or fluid intelligence (the Cognitive Abilities Test Nonverbal Battery). Two measures of students' attitudes were also employed: (1) the Intellectual Achievement Responsibility Scale, as an index of locus of control in the classroom, and (2) the School Sentiment Index, as a measure of attitudes toward the school environment. There was no unequivocal evidence for the superiority of open education in all areas of student achievement, although fifth grade open school students did significantly better than control students in the language arts. The results of the attitudinal measures were mixed and limited by sample size, but a significant sex by environment interaction emerged at grade five. In grade five, girls at the open school were more positive in their attitudes toward school than girls at the traditional school, whereas boys were more positive in the traditional school than in the open school. Three tables summarize the results. (Author/BH)