# Degree of freedom in DSGE-VAR

**URL:** <https://forum.dynare.org/t/degree-of-freedom-in-dsge-var/4892>\
**Category:** DSGE-VAR\
**Created:** [7 August 2015 04:15 UTC](https://forum.dynare.org/t/degree-of-freedom-in-dsge-var/4892 "2015-08-07T04:15:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![earsmall](https://forum.dynare.org/letter_avatar_proxy/v4/letter/e/b9e5f3/32.png) [@earsmall](https://forum.dynare.org/u/earsmall)\
**Post date:** [7 August 2015 04:15 UTC](https://forum.dynare.org/t/degree-of-freedom-in-dsge-var/4892/1 "2015-08-07T04:15:12Z")

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Hi, my question is not directly related to Dynare programming.  
It is about the theory in DSGE-VAR with reference to [dynare.org/DynareWiki/DsgeVar](http://www.dynare.org/DynareWiki/DsgeVar).

The question is, the prior distribution of forecasting error variance in DSGE-VAR follows an inverted Wishart distribution  
with degree of freedom LT-mp-m where LT is the number of artificial observations generated from DSGE model, m is the number of  
VAR model variables and p is the lag length.

Is there anyone who can explain why the degree of freedom is LT-mp-m ?  
or Could you introduce me some internet pages including proper explanation?

Thank you.

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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:** [7 August 2015 09:32 UTC](https://forum.dynare.org/t/degree-of-freedom-in-dsge-var/4892/2 "2015-08-07T09:32:10Z")

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Please take a look at Del Negro/Schorfheide (2004): Priors from general equilibrium models for VARs, International Economic Review. We have to check the page you refer to. The treatment of the constant term seems strange.