# IRF for two exogenous shock?

**URL:** <https://forum.dynare.org/t/irf-for-two-exogenous-shock/3694>\
**Category:** Dynare help (legacy posts)\
**Created:** [14 February 2014 13:32 UTC](https://forum.dynare.org/t/irf-for-two-exogenous-shock/3694 "2014-02-14T13:32:33Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Shreekar](https://forum.dynare.org/letter_avatar_proxy/v4/letter/s/ebca7d/32.png) [@Shreekar](https://forum.dynare.org/u/Shreekar)\
**Post date:** [14 February 2014 13:32 UTC](https://forum.dynare.org/t/irf-for-two-exogenous-shock/3694/1 "2014-02-14T13:32:33Z")

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Hi,

I have two stupid (most likely) questions.

1. I want to analyze simultaneously two exogenous shocks in a model (eg. two different productivity shocks) but I get two separate Impulse response functions corresponding to each shock respectively. How can I have a joint IRF as the result of the two exogenous shocks in the model?

2. I want to give an exogenous positive shock to the model but it should, at the same time, give a negative shock to another exogenous variable. The later shock is in a proportion to the first shock. In other words, a shock should also generates another exogenous shock in the model.

Best,

Shreekar

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**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [14 February 2014 14:14 UTC](https://forum.dynare.org/t/irf-for-two-exogenous-shock/3694/2 "2014-02-14T14:14:04Z")

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See [[3 exogenous shocks at a time](https://forum.dynare.org/t/3-exogenous-shocks-at-a-time/1393/1))

For a negative shock, just put a (-1) before the shock in the model equations.