At the outset, let me comment on the term “models” and their use. In my view the meaning of the word “model” must be very broad and not confined to econometric approaches. Each tool which could contribute to a better understanding of complex phenomena could receive this designation. But we must not forget that a model as a computer can give no absolute answer; the output must always be related to the input. Models are tools which help the human brain but cannot take its place.