With the debut of common assessments less than two years away, states and districts are worried about the accountability systems that hinge on those tests. A growing chorus of policy groups is urging more flexibility in how states evaluate teachers, label schools, and enforce other high-stakes consequences during what's likely to be a messy…

New York is ahead of most states in its work to design detailed curricula and professional development for the common core and to build brand-new tests to reflect them. What's unfolding in the Empire State as a result of that work illustrates the way the common standards can pressure changes in the education landscape, and torque the tensions…