Still as a student at the Faculty of Mathematics and Computer Sciences at the Warsaw University, back in the late 1980s, I assisted in the works on a model of the Polish economy carried out at the Faculty of Economic Sciences. Soon afterwards, as a result of the fundamental changes in the structure of the Polish economy, consisting in liberalisation of prices and opening to foreign trade, the model became useless as a tool of macroeconomic analysis. Nowadays, the changes observed in the Polish economy are neither so rapid nor radical any more. However, intensification of changes in the global economy, reported in the recent years, must have brought in many economic relations other than those known so far. There have been many structural changes whose force, permanence and significance cannot be assessed on an ongoing basis with the use of econometric models. In principle, such an assessment is feasible only after a few years, which - from 1 the point of view of pursuing an effective monetary policy - is too long a period . This is why in such periods the so-called soft data and information, obtained directly from entrepreneurs, gain particular significance. There are numerous examples of such changes taking place in many countries.
Another factor that is often indicated is the change in the economic policy of the Asian countries after the crisis of 1997-1998, when a decision was taken in many countries to establish huge foreign exchange reserves for the purpose of hedging against similar changes in the sentiment of financial markets in the future 12 . Other hypotheses indicate higher investment attractiveness of the USA in comparison to other regions, measured - inter alia - with the higher potential economic growth rate 13 . There exists another hypothesis, according to which such a high current account deficit is optimal 14 , in the face of the expected higher future growth rate of the American economy in comparison to that of other developed economies. This hypothesis is based on the assumption that Americans increase their present consumption financed from loans, anticipating high future earnings that will allow them to pay off the loans, which is perfectly correct. Finally, there are papers which try to prove that ... there is no deficit. The above-mentioned article by Hausmann and Sturzenegger 15 arguing for the existence of “dark matter” is an example of this approach. In spite of many attempts to prove that the US current account deficit is in fact lower than it is believed to be and that it is even desirable, a vast majority of academic economists and many central bankers are seriously alarmed by the scale of global imbalances.