The purpose of this study was to examine the influence of a PLC model as theorized by Hord (1997) and as influenced by Bandura's (1997) theory of self-efficacy on grade 4 mathematics and language arts literacy achievement on High-Stakes Criterion-Based Assessments (HSCBA). The researcher conducted this study in an urban New Jersey elementary setting and utilized a longitudinal non-experimental quantitative design. The researcher measured total population, ethnic sub groups and special education achievement through an analysis of the New Jersey Assessment of Skills and Knowledge (NJASK) among 1,479 4th grade students to determine if there was a statistically significant link between PLCs and student achievement levels. The researcher subsequently conducted a series of ANOVAs on the NJASK4 data obtained. The study results support the benefit of PLCs as capacity-building, efficacy-supporting structure that improves student achievement.