Policymakers treating school system structures like clock-work gears and cogs issue directives seeking school and classroom reforms and believe that administrators and practitioners will carry out these marching orders as directed in flow charts and policy manuals. Too many loose connections, unmapped but interdependent relationships, unpredictable events, political pressures and ambiguous directives combine into a web-like complex system confounding what policymakers seek, what administrators request, and what teachers end up doing.

Explaining Change and Stability in Classroom Practice | Larry Cuban on School Reform and Classroom Practice