Seite - 121 - in The Austrian Business Cycle in the European Context

121 cycles should lead to a reduction of cycles and hence to longer cycles and phases. The reduction of variation probably allowed the Bry-Boschan routine to detect more turning points than in the case of just filtered series. This leads to a reduction of the length of cycles and phases, as can be seen in Table A 10 a. Now the cycle length is reduced to around 17 quarters, from around 23 quarters for just filtered series. However, this is not a general feature of the dynamic factor model output, as it is the other way round for the Austrian construction sector (autF) and for German manufacturing production (gerCDE). The same puzzle arises when focussing on symmetries of business cycle phases. Regarding the common component, cycle phases are now more symmetric for the reference series than they were for the just filtered series. The time span of downswings (from a peak to a trough) and upswings (from a trough to a peak) is now close to nine quarters for both phases, whereas it differed substan- tially (7 quarters against 13 quarters) for the just filtered reference series. For other series like the Austrian construction sector (autf) and German manufacturing production (gerCDE), it is exactly the other way round: they now show more asymmetries in their cycli- cal behaviour. Both facts point to a rather arbitrary dating of the cycle in the case of first-order differences. Transformation by the dynamic fac- tor model leads to unsystematic changes of the properties of cy- cles when dated with the Bry-Boschan procedure. Thus, first-order differences again turn out to be an inappropriate method for the extraction of the cycle. The same problem shows up for HP-filtered series, albeit at a smaller scale. Again, the high-frequency part included in these se- ries leads to an unstable dating of turning points, which is reflected by the differences concerning the length of the cycle. Ta- ble A 1 O b shows a change in the length when compared with the just filtered series given in Table A 4 b. Only for few series, the dates of the common components turning points show a similar cycle