The progress of sixth-graders in elementary and middle schools was compared in terms of achievement test scores, attendance, discipline, and grade point average. Three groups of sixth-graders from the Austin schools were examined: (1) 1987-88 sixth-graders for 3 years (grades 6, 7, and 8); (2) 1988-89 sixth-graders for 2 years (grades 6 and 7); and (3) 1989-90 sixth-graders for 1 year. When achievement, as measured by the Iowa Tests of Basic Skills, was examined, the middle school transition (grade 5 to grade 6) seemed to be smoother than the junior high school transition (grade 6 to grade 7). In 1987-88, elementary school sixth-graders (ESSGs) generally performed better on achievement tests than did middle school sixth-graders (MSSGs); after 1987-88, there has been no difference between the performance of ESSGs and MSSGs on achievement tests. When ESSGs reach the seventh grade, they do not perform as well on achievement tests as do seventh-graders who attended the sixth grade in middle schools. By grade 8, there was no difference between achievement gains of students in middle schools and junior high schools. Middle schools disciplined students at higher rates and had slightly lower attendance rates than did elementary schools. During the period from grade 6 to grade 8, the achievement gap between high and low achievers became wider in both junior high and middle schools. These findings indicate the need for vigilance in assisting students to make the necessary social and cognitive transitions from elementary to middle schools. Ten figures present study data. (SLD)