Dynare forums

Hi everyone,

I have a question for clarification of the timing of impulse responses in Dynare. I am currently using the statement

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predetermined_variables k;

combined with a standard law of motion for capital

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k(+1)=(1-delta)*k+i;

Now I let Dynare compute impulse responses to some contemporaneous exogenous shock called epsilon (think of it for example as a temporary shock to TFP that enters the production function) by saying

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shocks;
var epsilon; stderr 1;

stoch_simul(order=1,irf=40) y k;

I realize that according to the manual, the shock hits at time t=1 on the x-axis in the resulting plots. However, I note that k also moves on impact (period 1), which should not happen as it is predetermined. Does Dynare internally shift predetermined variables to the old notation (i.e. k is used as k(-1)), so that the impulse response plotted is shifted by one period for predetermined states? I mean, does the impulse response to k at t=1 actually happen at t=2 or am I doing something wrong in my model? I would appreciate any help as I could not find any information in the documentation about the impulse response timing for predetermined variables.

Johannes

Hi,

Yes basically Dynare shifts the predetermined variables from one period, back to the old notation (i.e. k is used as k(-1)).

Best