The pressure on schools to improve student performance in middle school mathematics combined with the movement towards standards-based instruction leaves teachers searching for the most effective instructional practice and administration examining their role in improvement efforts. This study examines the effect on student achievement in middle school mathematics as a function of the quality of teacher collaboration interacting with administration presence during collaboration. This study used a quantitative research design in which seventh-grade mathematics teachers from two different middle schools in the same district with similar demographics taught the same standards-based unit of study and administered a common summative assessment at the end of the unit. Additionally, all teachers evaluated the quality of their job-alike collaboration during this unit using the Teacher Collaboration Assessment Rubric (TCAR). The overall research suggested that while years of experience had a small significant effect on the achievement of students, a larger predictor of achievement was higher quality of teacher collaboration when administration was present during collaboration meetings. This study suggests that administration presence during teacher collaboration and modeling professional learning communities (PLC) can improve the quality of collaboration and serve as a better predictor of student achievement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]