This study addresses a problem of practice at Nipmuc Elementary School (NES), a large urban elementary school in New England. State standardized test data and student writing samples showed that students were performing well-below grade level in writing. The primary factors driving this problem included teachers' lack of knowledge and low self-efficacy, and students' lack of motivation and engagement. To ameliorate this problem, a team of fourth-grade teachers at NES participated in a four-week series of professional learning community (PLC) meetings focused on understanding the Empowering Writers Annotation and Analysis (EWAA) process, a key part of a newly-adopted writing curriculum. A mixed-methods design was used to determine the impact of this project on teachers' sense of efficacy for writing instruction. Findings show an increase in efficacy for the fourth-grade teacher team, while a control group of third-grade teachers show no change in efficacy over the same time period. Five main themes developed through an analysis of qualitative data: Exposure to a variety of experiences about the EWAA protocol helped increase teachers' awareness of the importance of enriching their pedagogical content knowledge; PLCs affected teachers' sense of efficacy for teaching writing by developing clearer goals; sustained teacher engagement with the PLC meetings provided a bridge from theory to practice, extending beyond the study into teachers' lived classroom experiences; peer dialogue and feedback supported teachers in thinking through their practice; and a lack of evidence of students' independent abilities prevented teachers from being able to assess student learning. [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.]