Hi，everyone！I wonder know if I want to add a shock that its steady state is not equal to one(**i.e.ln(ψ）=（1-ρ）ln（steady_state (ψ)+ρln（ψ(-1)）+ ε**）,how should I express in dynare code and how to compute the steady state of shock. I already know how to add a shock that its steady state is equal to 1(which is a special case of the above equation, **i.e ln(ψ）=ρln(ψ(-1)+ ε)** .I’ve go through the forum but cannot find the answer. I feel really confused about this.

If it is possile, can you give me an **example**, Thanks in advance!

Define the desired steady state value as a parameter `psi_bar`

and use

```
ln(psi)=(1-rho)*psi_bar+rho*psi(-1)+eps_psi
```

Thank you Professor！ But where does the desired steady state value from? How to choose it？Is chosen by myself randomly or from some essays or classical theories or I need to do some calculations in advance？Thanks agin.

It’s an exogenous process. Nothing in the model tells you what it’s value should be. That’s why most multiplicative shock process are normalized to mean 1.

I understand! Thanks a lot.