1. A ventilation system, comprising: 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 patient effort, 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 calculate a gas delivery metric, wherein the gas delivery metric varies as a function of the patient effort value; and cause a gas to be delivered consistent with the gas delivery metric.