Dynamic Identification in VARs

Résumé

Most macroeconomic models, view economic outcomes as being generated by a combination of endogenous and exogenous dynamic forces. In particular, the exogenous forces are generally modeled as a set of independent dynamics processes. In this paper we begin by showing that this dual dynamic structure is sufficient to identify the entire set of structural impulse responses inherent to any such model. No extrarestrictions are needed. We then use this result to suggest how it can be used to evaluate common SVAR restrictions (impact restrictions, long run restrictions and proxy-VAR).