A system for assisting a rescuer in providing resuscitative treatment to a victim, the system comprising: at least one motion sensor configured to generate signals indicative of motion of the chest of the victim during cardiopulmonary resuscitation chest compressions; at least one output device; and a processor, a memory, and associated circuitry communicatively coupled to the at least one motion sensor, wherein the processor is configured to: receive the signals indicative of the motion of the chest, generate a compression waveform based on the signals indicative of the motion of the chest, detect, in the compression waveform, features (901-908, 910-916) characteristic of the chest compressions, compare the detected features to predetermined criteria that distinguish between manually delivered chest compressions and automated chest compressions delivered by an automated chest compression device (200, 260), the predetermined criteria comprising threshold values or ranges associated with automated chest compressions, and determine whether the chest compressions are the manually delivered chest compressions or the automated chest compressions based on the comparison by determining if the features meet the threshold values or are within the ranges associated with automated chest compressions, characterized in that the processor is configured to control the at least one output device to selectively provide chest compression depth feedback and chest compression rate feedback if the chest compressions are determined to be the manually delivered chest compressions and to withhold the chest compression depth feedback and the chest compression rate feedback if the chest compressions are the automated chest compressions. at least one motion sensor configured to generate signals indicative of motion of the chest of the victim during cardiopulmonary resuscitation chest compressions; at least one output device; and a processor, a memory, and associated circuitry communicatively coupled to the at least one motion sensor, wherein the processor is configured to: receive the signals indicative of the motion of the chest, generate a compression waveform based on the signals indicative of the motion of the chest, detect, in the compression waveform, features (901-908, 910-916) characteristic of the chest compressions, compare the detected features to predetermined criteria that distinguish between manually delivered chest compressions and automated chest compressions delivered by an automated chest compression device (200, 260), the predetermined criteria comprising threshold values or ranges associated with automated chest compressions, and determine whether the chest compressions are the manually delivered chest compressions or the automated chest compressions based on the comparison by determining if the features meet the threshold values or are within the ranges associated with automated chest compressions, characterized in that the processor is configured to control the at least one output device to selectively provide chest compression depth feedback and chest compression rate feedback if the chest compressions are determined to be the manually delivered chest compressions and to withhold the chest compression depth feedback and the chest compression rate feedback if the chest compressions are the automated chest compressions. receive the signals indicative of the motion of the chest, generate a compression waveform based on the signals indicative of the motion of the chest, detect, in the compression waveform, features (901-908, 910-916) characteristic of the chest compressions, compare the detected features to predetermined criteria that distinguish between manually delivered chest compressions and automated chest compressions delivered by an automated chest compression device (200, 260), the predetermined criteria comprising threshold values or ranges associated with automated chest compressions, and determine whether the chest compressions are the manually delivered chest compressions or the automated chest compressions based on the comparison by determining if the features meet the threshold values or are within the ranges associated with automated chest compressions, characterized in that the processor is configured to control the at least one output device to selectively provide chest compression depth feedback and chest compression rate feedback if the chest compressions are determined to be the manually delivered chest compressions and to withhold the chest compression depth feedback and the chest compression rate feedback if the chest compressions are the automated chest compressions.