This study attempted to answer two major questions: (1) Does a significant difference exist between the mean gain scores for achievement in reading and mathematics, as measured by the Comprehensive Test of Basic Skills (CTBS), among students from three different architectural school settings (open space, traditional, and mixed); and (2) Do reading and mathematics mean gain scores indicate a significant interaction between socioeconomic status (SES) and school setting? A total of 388 students who were in the third grade in 1977-78 and in the fifth grade in 1979-80 at the same schools participated in the study. In the third grade, students were administered Form S of the CTBS, and at the fifth grade they were administered the parallel Form T. Reading and mathematics scores in grade three were compared with those in grade five to obtain gain scores for each student. No significant differences were found between mean gain scores in mathematics or reading from the two SES groups or between mean gain scores in mathematics for students attending the three different types of school settings. The only significant F ratio was found for mean gain scores in reading for the students from the three settings--open, traditional and mixed. This difference, however, could not be solely attributed to any specific school setting. The findings were consistent with the available research on the subject. (Author/MP)