The authors comment on Porter, McMaken, Hwang, and Yang's recent analysis of the Common Core State Standards for Mathematics by critiquing their measures of the focus of the standards and the absence of an assessment of coherence. The authors then consider whether the standards are an improvement over most state mathematics standards by discussing whether the core mathematics ideas on which they focus are appropriate, whether individual standards are organized into coherent learning progressions, and whether their implementation is feasible. They question whether schools and districts currently have the capacity to support effective implementation, and they call for improvement-oriented investigations that can inform the development of effective implementation models.