Seite - 113 - in The Austrian Business Cycle in the European Context

113 der to capture possible asymmetries of the business cycle, spans are calculated for the time elapsed between peaks and troughs (P to T) and troughs and peaks (T to P), separately. Due to the reasons cited above, the focus lies again on the BK- fil- tered data, the results of which are compared with HP- and first- order-difference-filtered data. Table A 4 c shows for the reference time series (autGVAex) the time elapsed between two consecu- tive peaks or troughs of around 15 quarters, i.e. approximately 4 years. This result contrasts the ones of the HP- and first-order- difference-filtered data, which is reproduced in Table A 4 band a, respectively. Both show a longer cycle length of roughly 20 quar- ters or five years. Furthermore, they suggest an asymmetry of phases, with a time span of 12 to 13 quarters from a trough to a peak and 7 quarters from a peak to a trough. This stylised fact of longer phases of upswings than downswings is frequently reported in business cycle analysis, but is not confirmed in the BK-filter case. In order to check, whether this kind of asymmetry is linked to the method of extraction of business cycle variations, the averages of phase and cycle length over all series are reported in the last row of the tables. Looking at the results for first-order differences, no such asymmetry seems to exist. If anything, the time elapsing from a peak to a trough, i.e. close to 11 quarters, even seems to be somewhat longer, by around 1 quarter, than the upswing phase. However, for HP filtered data, the mentioned asymmetry seems to exist. Upswing phases, with more than 12 quarters, are longer than downswings, which last less than 1 O quarters. In the case of the BK filter, again no asymmetries emerge overall. 8.3.1.1 Conclusions for the ad-hoc-determined reference business cycle The inclusion of variances higher than the frequency band of busi- ness cycles in the first-order-difference and HP-filter case yields for both data sets quite similar leading and lagging properties ac-