A method is disclosed for evaluating a model, characterized as being a computer executable device and circuit simulator. The method includes accepting measured parameters of devices, which devices are essentially identical with, or are actually from, a simulated circuit instance. The model is executed with adjusted input parameters to generate simulated values for properties of the circuit instance. These simulated values are compared with measured values of the same properties. The goodness of the model is determined based on the degree of direct, or statistical, agreement between the simulated and measured values.