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Two shocks simultaneously in a model

PostPosted: Sun Jul 24, 2016 12:17 am
by Reese2101
Hi, I am new to Dynare. But I was thinking if it is possible to "combine" two IRF's. For example give the model a negative demand shock and simultaneously shock a different process and get a combined result without using correlation between shocks. I have a model that I would like to shock with a negative demand shock and at the same time shock another process representing Central bank purchase of long-term bonds so as to look at how these purchases can affect equilibrium alongside a Taylor rule. Dynare only prints IRF's for each individual shocks.
Regards
Peter

Re: Two shocks simultaneously in a model

PostPosted: Sun Jul 24, 2016 10:39 am
by jpfeifer
If you are working with a linearized model (order=1), the IRF to a joint shock is the sum of the individual IRFs. That way you can create any linear combination. If you want to do this more formally, you can use the simult_-function to generate any combination you like (even at higher order). See https://github.com/JohannesPfeifer/DSGE_mod/blob/master/RBC_news_shock_model/RBC_news_shock_model.mod for an example