Abstract: A circuit actively monitors and measures the amount of MOS device degradation due to, for example, the hot electron effect, and makes compensatory adjustments to device voltage levels or clock speed to maintain desired levels of functionality and performance. Monitoring can be done separately for NFET and PFET devices to selectively adjust for different degradation rates between the two. In operation, the monitor circuit compares the performance of a stressed device to a reference device, that is, an unstressed device which has not been degraded by the hot-electron effect. The monitor circuit outputs a signal indicating the amount of device degradation. This signal is used to adjust the supply voltage to that device or to the chip or otherwise compensate for the degradation. The monitor circuit can be formed on-chip or off-chip.