Methods and systems are disclosed for controlling an exhaust gas recirculation valve in an engine by determining errors in exhaust backpressure estimates and adapting EGR flow estimations based on these errors to meet target EGR dilutions in the engine. In one example approach, a method comprises adjusting valve position based on desired EGR flow and estimated EGR flow, where the estimated flow is based on estimated exhaust backpressure, and the estimated exhaust backpressure is updated based on errors between actual and desired intake oxygen concentration.