The paper attempts an explanation of the alleged "lack of adequate economic models" to predict and eventually avoid - through certain policy recommendations - the recurrent global or individual economic or financial and fiscal crises. In the author’s opinion, in the controversy over the "rational expectation approach” and the design of dynamic and stochastic models, have been neglected some important underlying issues in economic performance, such as the very crucial institutional enforcement basis on which economic agents operate, including particularly government agents. The Public Choice School and modern Institutional Economics can help to understand the limitations and possibilities faced when seeking to improve the economic theory in its status as “science”.