Measuring the degradation of modern devices subjected to bias temperature stress has turned out to be a formidable challenge. Interestingly, measurement techniques such as fast- Vth, on-the-fly ID,lin, and charge-pumping give quite different results. This has often been explained by the inherent recovery in non-on-the-fly techniques. Still, all these techniques deliver important information on the degradation and recovery behavior and a rigorous understanding linking these results is still missing. Based on our detailed studies of the recovery, we propose a new measurement technique which allows the simultaneous extraction of two distinctly different components, a fast universally recovering component and a slow, nearly permanent component.