As one of the foremost promoters of the Common Core Standards, Duncan certainly has a voice in the conversation about education in the United States. In this speech he makes a clear and important distinction between standards and curriculum, stating:
We need to be very clear about definitions here.
Standards—learning standards, academic standards—are the goals, typically set by states, for what students should know by a certain age.
Curriculum—on the other hand—is what teachers teach to help students meet those standards. Curriculum is generally chosen at the district or even the school level—and in many cases individual teachers actually decide on the curriculum and classroom content.