Teacher observation and teacher evaluation are a given in American schools, and Charlotte Danielson's work in teacher effectiveness and professional practice has guided evaluation efforts for many years. There is a new, big kid in town, however. As Race to the Top requires documentation of student growth, and research shows that teacher effectiveness is a key factor in student learning, people see full implementation of performance-based teacher-evaluation systems in states and school districts across the nation. The goal of performance-based teacher evaluation is actually two-fold: first, to document teacher effectiveness and, second, to guide professional growth. Educators must not lose sight of the second goal, professional growth, in their focus on the first; in fact, teacher effectiveness is a logical outcome of quality professional growth. Well-prepared teachers fully involved in professional learning are more effective teachers. States are at various stages in the development and implementation of performance-based teacher evaluation for school librarians. As connected educators, school librarians have rich and deep personal learning networks that can be used strategically for professional growth, and data from summative evaluations should be used to drive this growth.