# Persistency in IRFs

**URL:** https://forum.dynare.org/t/persistency-in-irfs/28295
**Category:** Stochastic simulations
**Created:** [2 March 2026 10:00 UTC](https://forum.dynare.org/t/persistency-in-irfs/28295 "2026-03-02T10:00:29Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Random.t](https://forum.dynare.org/letter_avatar_proxy/v4/letter/r/eada6e/32.png) [@Random.t](https://forum.dynare.org/u/Random.t)
#### Post date: [2 March 2026 10:00 UTC](https://forum.dynare.org/t/persistency-in-irfs/28295/1 "2026-03-02T10:00:29Z")

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Hi everybody,

I cannot undestrand why my IRFs to a tfp shock in this two agent two sector environmental model are so persistent and seem to revert back to the steady state after hundreds of periods, even with a plausible value for the persistence of the TFP shock (0.9).

[tank.mod](https://forum.dynare.org/uploads/short-url/et5xD2asMCY8mkt5CkkhgPaBUen.mod) (1.8 KB)

[tank\_steadystate.m](https://forum.dynare.org/uploads/short-url/7UsicbJ5tdzXPRjh0sKQxJlz1Dr.m) (2.0 KB)

[findss\_tank.m](https://forum.dynare.org/uploads/short-url/yMYphTgygn2rH9D6HdaFZ5oQGgv.m) (1.2 KB)

Thank you so much

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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: [3 March 2026 08:40 UTC](https://forum.dynare.org/t/persistency-in-irfs/28295/2 "2026-03-03T08:40:48Z")

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The half-life of your shocks seems moderate. Mostly it’s less than 10 years. With capital accumulation that is not unusual.