A combined experimental and simulation study on a set of 4 OLEDs with 2 systematically varied guest dopants in the emission layer is presented. A numerical electro‐optical model is employed, demonstrating one consistent parameter set that describes both steady‐state and ac characteristics of all devices. The model accounts for charge transport and trapping, polar layers, and excitonic loss processes inducing an efficiency rolloff that can be correlated with the shape of the emission zone and the guest dopant concentrations. Furthermore, starting from the resulting parameter set, we show routes for optimized devices with a reduced roll‐off.