# A problem with eigenvalues equal to 1 and -1

**URL:** <https://forum.dynare.org/t/a-problem-with-eigenvalues-equal-to-1-and-1/5546>\
**Category:** Dynare help (legacy posts)\
**Created:** [30 May 2016 08:12 UTC](https://forum.dynare.org/t/a-problem-with-eigenvalues-equal-to-1-and-1/5546 "2016-05-30T08:12:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![moslem6333](https://forum.dynare.org/letter_avatar_proxy/v4/letter/m/958977/32.png) [@moslem6333](https://forum.dynare.org/u/moslem6333)\
**Post date:** [30 May 2016 08:12 UTC](https://forum.dynare.org/t/a-problem-with-eigenvalues-equal-to-1-and-1/5546/1 "2016-05-30T08:12:12Z")

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Hi,  
I’m estimating a DSGE model using Dynare. When I use “steady; check;” command, I find that there is tow eigenvalues equal to 1 and -1. Does that mean the endogenous variables are unit root? How to find that variable? What should I deal with it? Is there any consequence if there is a unit root variable in the model?

here is my mod file based on Medina, J. P. and C. Soto Model for The Chilean economy

Thank you,  
[iran\_data1600.m](https://forum.dynare.org/uploads/default/original/2X/e/ec514cfe479bda7428cdd59f1f8e6417ce00e62b.m) (24.9 KB)  
[Iran\_Exo\_final.mod](https://forum.dynare.org/uploads/default/original/2X/6/623057b22df4541f15714b5687a2eb7955fc70d9.mod) (23.7 KB)

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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:** [1 June 2016 08:39 UTC](https://forum.dynare.org/t/a-problem-with-eigenvalues-equal-to-1-and-1/5546/2 "2016-06-01T08:39:32Z")

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Yes, that means there are unit roots. To find them, you can look at the IRFs with a long horizon. The variables that do not return to 0 have a unit root.  
Whether that is problematic depends on whether the unit roots are an economic feature of the model or due to a bug in your mod-file. If it is the former, there is no reason to worry. You just have to keep in mind that you will need the

```auto

```

in estimation.