This approach provides the SVAR with the decomposition of shocks into permanent and
transitory and gives economic content to the long-run or cointegrating relations that
underlie the transitory components. In the simple example of Blanchard and Quah this
task is trivially achieved by assuming real output to be I(1) and the unemployment rate
to be an I(0) variable. To have shocks with permanent effects some of the variables in the
VAR must be non-stationary. This provides a natural link between the SVAR and the
unit root and cointegration literature. Identification of the cointegrating relations can be
achieved by recourse to economic theory, solvency or arbitrage conditions. (Garrett, Lee,
Pesaran and Shin, 2003a). Also there are often long-run over-identifying restrictions that
can be tested.