Analiza spektralna syntetycznych wskaźników koniunktury dla gospodarki polskiej

The composite indicators of general business activity for Poland (GCI1, GCI2, GCI5), based on monthly data for major sectors of the economy covering the period of 1975-1995, have been subject to spectral analysis using the Turkey-Hanning and Parzen windows in order to discriminate periodic fluctuations. Apart from the seasonal oscillations seen in the raw data, the time series smoothed by ARIMA display distinct spectral peaks at low frequencies corresponding to the range of 72-144 months and less pronounced peaks for the period of 36 months. This may suggest the existence of major (Juglar - type) cycles seen in the detrended GCI1, GCI2 and GCI5 time series. Using the OECD PAT procedure for the identification of turning points reveals a well pronounced business cycle for the length of 9-10 years, splitted by a minor cycle of ca 3 years. However, due to the relatively short period of observation, these findings should be verified by further research.