Seite - 166 - in The Austrian Business Cycle in the European Context

166 Boschan routine, as compared with just filtered series. This is quite in line with theory, as the dynamic factor model is used for clean- ing idiosyncratic cycles. Only in the case of first-order-differenced series, the number of cycles detected increases. This can be ex- plained by the fact that the large number of ups and downs of just first-order-filtered time series is reduced by the dynamic factor model by idiosyncratic ones. This reduction led to a lower number of local minima and maxima, making it easier for the Bry-Boschan routine to locate them. Therefore, the BK-filter approach seems to be for theoretical as well as for practical reasons, the superior preparation for dating a cycle. Comparing the dating calendars for the Austrian business cycle of just BK-filtered series with the ones represented by their common component, one can observe that the number of cycles is lower in the latter case. A short- lived cycle reflected in just fil- tered Austrian gross value added (without agriculture and forestry) starting with a trough in 3Q 1983 and a following peak one year later has been recognised as of idiosyncratic nature and was therefore filtered out. The absence of this cycle for that period is confirmed by all studies compared with in chapter 9. They neither show this cycle for the euro area nor for Austria 130• There is only one further significant difference between just BK- filtered series and the ones transformed by the dynamic factor model, namely a trough following the peak around the change of the year 1994-1995. Whereas this is dated in the first case in the second quarter of 1997, it is located in the first quarter of 1999 by the common component approach. To check this again, results are compared with other studies. Unfortunately, only one of the studies presented in chapter 9 can be compared for this time span. Artis - Marcellino - Proietti (2004) confirm both troughs and 130 Only three studies provide a comparable dating calendar: Artis - Krolzig - Toro (2004), Hahn -Walterskirchen (1992) and the dating calendar for the euro area by the CEPR.