A method for characterizing an integrated circuit that selecting at least two devices from an integrated circuit for measuring light emission, wherein each of the at least two devices have experienced a different level of stress, applying power to the integrated circuit, and measuring the light emission from the at least two devices. The method also includes comparing the light emission that is measured from the at least two devices, wherein a difference between the light emission that is measured from the at least two devices greater than a predetermined ratio indicates that at least one of the devices from the at least two devices has a below specification performance.