Policy makers are primarily interested in fluctuations in the level of activity - the classical cycle. Academics have in recent times focused their efforts on studying fluctuations and co-movement in aggregate variables that have been rendered stationary after some appropriate transformation....

Macroeconomics has a long tradition of inspecting and interpreting patterns in graphs of aggregate data. However, the move towards more precise quantification of macroeconomic phenomena has seen academics shift away from a study of turning points, which are a natural and obvious way of...