A comparison of seventh and eighth graders' behaviors and achievement in K-8 and junior high schools shows K-8 students performing more favorably in all areas. Students in nine K-8 schools and nine junior high schools in the City School District of New York City were compared on reading achievement, attitude toward school, students' self-esteem, pupils' perceptions of teachers' control methods, and school attendance. Significant differences were found between the mean scores of K-8 and junior high students for all the five variables. The K-8 students scored significantly higher in reading, indicated a more positive attitude toward school, and reflected a stronger self-esteem than their peers in junior high. The K-8 students also perceived their teachers' pupil control methods to be more humanistic. Moreover, they were absent significantly fewer days than were junior high students. The school grade system, then, does affect cognitive and affective school outcomes. (Author/JW)