Despite recognized gains in student achievement in the United States, the achievement gap between economically disadvantaged students and non-economically disadvantaged students expands. Understanding the larger context of student learning is incumbent upon school leaders who must consider the impact of socioeconomic status, residency, and social capital. These factors influence the effectiveness of teaching practices implemented to close the gap. By focusing on instructional leadership involvement in Professional Learning Communities (PLCs), this qualitative research study investigated social constructivism's impact on teacher capacity in high-needs schools in a large urban district. This study explored three specific themes: designing and implementing PLCs by instructional leaders, designing and implementing PLCs by teachers, and the influence on teacher efficacy. [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.]