The present invention comprises a cardiopulmonary resuscitation (CPR) feedback device and a method for performing CPR. A chest compression detector device is provided that measures chest compression during the administration of CPR. The chest compression detector device comprises a signal transmitter operably positioned on the chest of the patient and adapted to broadcast a signal, and a signal receiver adapted to receive the signal. The chest compression detector device also comprises a processor, operably connected to the signal transmitter and the signal receiver. The processor repeatedly analyzes the signal received to determine from the signal a series of measurements of compression of the chest, and feedback is provided to the rescuer based on the series of measurements.