A desire to discover a preview of the future in the present makes people resort to various tricks. Predictions of economic development may be based on simple extrapolation, on sophisticated econometric models, on methods of “technical analysis”, on surveys of consumers and entrepreneurs, on observations that are unfit for formalization, made by experts and analytics, etc. System of leading indicators is one of the most widely used methods of anticipation of future economic activity. The idea behind this approach is simple and clear: there should be an “early warning” system to forecast when the economy will shift from expansion to recession (or on the contrary, from recession to expansion). In other words, we have to choose the indicators, which get to their turning points earlier than the economy in general.
Then, whenever the leading indicator gets to its peak or to its trough, we are able to predict a forthcoming peak or trough in the business activity in general. This idea was first put unto practice in the United States in the 1930’s. Regular publications of appropriate indicators were launched in the late 1960’s, and they are carried on today (see [5]). In the 1980’s, the OECD Statistics Directorate started construction of leading indicators for its member countries (see [6]). In the 1990’s, leading indicators for Turkey, Korea, Hungary, and Poland were developed under the supervision of the OECD (see [7a], [7c], [7d]). In addition to commonly used “official” indices, some “designers’ indicators” were introduced, with subtle variations in handling the initial statistical data (see, for example, [7b] and [8]).