When a model is structurally complete and simulates properly, calibration of the model can proceed to fit the model to this observed data.
Dynamic models are often very sensitive to the values of constant parameters.
If you want to calibrate your parameters so the model behavior matches observed data, you may need to experiment with thousands of combinations of different parameter values. Vensim calibration makes this procedure automatic. You specify which data series you want to fit and which parameters you want to adjust, then Vensim automatically adjust parameters to get the best match between model behavior and the data. There are no limits on the numbers of parameters to adjust or data series to fit. Over the last century, the conversion of U.S. households to electricity follows a pattern of diffusion, represented by a Bass Diffusion model.