Systems, methods, and devices for determining whether a medical sensor has been properly applied to a patient are provided. In one embodiment, a patient monitor having such capabilities may include a medical sensor interface and data processing circuitry. The medical sensor interface may receive physiological data from a medical sensor applied to a patient. The data processing circuitry may be capable of being trained, using a learning-based algorithm, to determine whether the received physiological data indicates that the medical sensor has been properly applied to the patient.