1. A ventilation system, the ventilation system comprising: a graphical display; a processor communicably coupled to a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to: receive a measured pressure value; receive a net flow value; calculate a patient effort value based on a relationship between the measured pressure value, the net flow value, and an estimated normalized prediction error, wherein the estimated normalized prediction error is based at least in part on a current estimated value of a parameter vector; and plot the patient effort value to the graphical display.