An important shift in thinking about teacher quality is underway. The demand for highly qualified teachers is slowly, but surely, being replaced by a call for highly effective teachers. The change is more than just semantics. Policymaking around improving teacher quality to date has focused almost exclusively on qualifications: teacher credentials, majors, degrees, licensing. But increased accountability for student learning and compelling research showing that teachers are the single most important school-based drivers of student achievement are moving the field towards a decidedly performance-based focus on teacher quality. How do efforts in Colorado compare to other states? And what are the implications of this paradigm shift for teacher preparation?