Concern about gain: is this the best measure of performance of cardiovascular reflexes?

Open-loop gain is commonly used as a measure of the effectiveness of cardiovascular reflex control systems. There is no evidence that directly measured baroreflex gain for heart rate gives useful information about blood pressure control in human or experimental hypertension. Calculation of open-loop gain for blood pressure from closed-loop observations requires many assumptions to be made. Calculation of the independent and interactive effects of reflex inputs by factorial analysis may be more versatile, and give a more useful expression of the actions and interactions of cardiovascular reflexes in response to physiological disturbances, than does the calculation of gain.