A computer-implemented method for obtaining a digital representation of user engagement with audio-video content includes playing digital data comprising audio-video content by an output device that outputs audio-video output based on the digital data and receiving sensor data from at least one sensor positioned to sense an involuntary response of one or more users while engaged with the audio-video output. The method further includes determining a Content Engagement Power (CEP) value, based on the sensor data and recording the digital representation of CEP in a computer memory. An apparatus is configured to perform the method using hardware, firmware, and/or software.