Educating students to meet high accountability standards and even more importantly preparing students to be competitive in a complex and demanding world requires schools to become high functioning organizations. This mixed-method study examined the relationship between professional learning communities and the collective efficacy in 10 elementary schools that participated in the Professional Learning Communities Institute (PLCI) in a large suburban school district outside Washington, DC. The implementation of the PLCI allowed the researcher to analyze these relationships in schools receiving structured and deliberate professional development in becoming professional learning communities as well as the effect this experience had on the beliefs of the group about their ability to make a difference for their students. The researcher analyzed survey and interview data through the lens of the characteristics of professional learning communities as outlined by Hord (1997) and the sources of efficacy as defined by Bandura (1997).

 The findings from this study revealed a significant relationship between the five dimensions of professional learning communities and collective efficacy. The characteristics of professional learning communities of shared leadership, shared vision, collective learning, supportive conditions, and shared personal practice work in a school organization to strengthen the collective efficacy of staff. The professional development that the schools received in becoming professional learning communities promoted collective efficacy.

 Although the 10 schools demonstrated strong collective efficacy, in general, there were some differences between schools. This study found that some variables influenced the perceived collective efficacy in the schools surveyed. There was a moderate inverse significant relationship between poverty level and collective efficacy. Low-poverty schools had higher collective efficacy than high-poverty schools. The length of time that teachers were in their current school was mildly related to the collective efficacy in that school. There was a negative mild relationship between the teachers' number of years of experience and the poverty level of the school.