Methods and apparatus to determine a power state of an information presentation device. The method includes measuring power drawn by the information presentation device during a calibration period to generate a log of measurement values, determining, by executing an instruction with a processor, respective counts indicating respective numbers of times respective different ones of the measurement values were detected during the calibration period, and determining, by executing an instruction with the processor, a first threshold based on at least one of the counts. The method also includes determining whether the presentation device is in an ON state based on a comparison of measured power drawn by the information presentation device after the calibration period to the first threshold.