These simulators also provide a means of evaluating the dynamic performance of the NIBP monitor by simulating the dynamic signals that the occlusive cuff would sense if placed on a patient's arm. However, while they are useful in looking at long-term trends of unit performance, they are not necessarily useful in evaluating device accuracy. Since NIBP monitors calculate their readings based on an algorithm, and the simulators use a similar algorithm to generate their signals, if the two algorithms are not exactly matched, then what the simulator states the pressure should be may differ from the pressure that the monitor indicates. It is also necessary to take several readings at each setting and average them; this average, over time, should remain constant for each individual NIBP monitor.