Discussion paper

DP17886 External Instrument SVAR Analysis for Noninvertible Shocks

We propose a novel External-Instrument SVAR procedure, the Generalised External-Instrument SVAR, to identify and estimate the impulse response functions, regardless of the shock being invertible or recoverable. When the shock is recoverable, we also show how to estimate the unit variance shock and the ‘absolute’ response functions. When the shock is invertible, the method collapses to the standard External-Instrument SVAR procedure. We show how to test for recoverability and invertibility. We apply our techniques to a monetary policy VAR. It turns out that, using standard specifications, the monetary policy shock is not invertible, but is recoverable. When using our procedure, results are plausible even in a parsimonious specification, not including financial variables.
Contrary to previous findings, monetary policy has significant and sizeable effects on prices.


Forni, M, L Gambetti and G Ricco (2023), ‘DP17886 External Instrument SVAR Analysis for Noninvertible Shocks‘, CEPR Discussion Paper No. 17886. CEPR Press, Paris & London. https://cepr.org/publications/dp17886