# Growth of variables and unit root

**URL:** https://forum.dynare.org/t/growth-of-variables-and-unit-root/3156
**Category:** General DSGE Modeling
**Created:** [15 May 2013 06:26 UTC](https://forum.dynare.org/t/growth-of-variables-and-unit-root/3156 "2013-05-15T06:26:55Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![tomnilson40](https://forum.dynare.org/letter_avatar_proxy/v4/letter/t/779978/32.png) [@tomnilson40](https://forum.dynare.org/u/tomnilson40)
#### Post date: [15 May 2013 06:26 UTC](https://forum.dynare.org/t/growth-of-variables-and-unit-root/3156/1 "2013-05-15T06:26:55Z")

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Hi Dynare guys,

I need to add the growth of some variables such as (x dot t)= (xt) - (xt-1) into my model but this creates the unit root problem and taking a long time for the variables to get back to the steady state. Does anyone know how to deal with this?! (I give a zero initial value for all the variables).

Any help would be appreciated.

Cheers

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### Author: ![Start](https://forum.dynare.org/letter_avatar_proxy/v4/letter/s/2bfe46/32.png) [@Start](https://forum.dynare.org/u/Start)
#### Post date: [6 July 2018 17:55 UTC](https://forum.dynare.org/t/growth-of-variables-and-unit-root/3156/2 "2018-07-06T17:55:50Z")

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Hi there ı have faced the same problem, have you fixed it? Is therd anyone to help?

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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: [9 July 2018 20:16 UTC](https://forum.dynare.org/t/growth-of-variables-and-unit-root/3156/3 "2018-07-09T20:16:25Z")

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1. The initial question does not make sense. A unit root variable will not go back to steady state.
2. Sometimes, one can divide by the stochastic trend to end up with a stationary model.
3. But there are models where the unit root is a feature. In this case, there is nothing you can do about it.