second moments vary between simulations

As Dynare 4 is now the main version, this forum is now closed. Please, post
on the Dynare Help forum
Forum rules
As Dynare 4 is the current Dynare version, there forum is now close. Post new question in the Dynare Help Forum.

second moments vary between simulations

Postby Ansgar » Wed Jan 09, 2008 1:03 pm

Dear all,
a happy and sucessful New Year to everyone. I am facing the following problem: I am conducting a stochastic simulation using the second order approximation (Schmitdt-Groehe Uribe). The second moments (sd., autocorrelations) and also the variables means differ a lot from simulation to simulation. Sometimes they are very close to the results from a first order approximation, but often they are really far away. How can I render my results more robust? Is increasing the number of periods the answer?
Best,
Ansgar
Ansgar Rannenberg
IMK
Tel.: +49/211/7778113
Ansgar
 
Posts: 46
Joined: Tue Jun 26, 2007 11:35 am
Location: Düsseldorf

Re: second moments vary between simulations

Postby StephaneAdjemian » Wed Jan 09, 2008 1:51 pm

Hi Ansgar,

Yes the moments (second and first order) obtained with stochastic simulations may vary quite a lot from simulation to simulation.

To get a more robust evaluation of the moments, you may :

[1] Compute theoretical moments (but this would be meaning less for second order moments).

[2] Increase periods (the size of the simulated time series).

In some case the simulated time series and so the moments may diverge, and this can explain large deviations with respect to the moments associated to a first order approximation of the model. This is a well known issue (see the papers by Schmidt-Grohé and Uribe or Sims et al.). To overcome this difficulty you may reduce the size of the exogenous shocks or implement the prunning algorithm advocated by Sims.


Best,
Stéphane.

Ansgar wrote:Dear all,
a happy and sucessful New Year to everyone. I am facing the following problem: I am conducting a stochastic simulation using the second order approximation (Schmitdt-Groehe Uribe). The second moments (sd., autocorrelations) and also the variables means differ a lot from simulation to simulation. Sometimes they are very close to the results from a first order approximation, but often they are really far away. How can I render my results more robust? Is increasing the number of periods the answer?
Best,
Ansgar
StephaneAdjemian
 
Posts: 429
Joined: Wed Jan 05, 2005 4:24 pm
Location: Paris, France.

Postby Ansgar » Sat Jan 12, 2008 6:52 pm

Dear Stephane,
many thanks, I have now tested for a unit root in the observations I have generated and the unit root can not be rejected. So it seems that it was that. Many thanks!
Best,
Ansgar
Ansgar Rannenberg
IMK
Tel.: +49/211/7778113
Ansgar
 
Posts: 46
Joined: Tue Jun 26, 2007 11:35 am
Location: Düsseldorf


Return to Dynare version 4

Who is online

Users browsing this forum: No registered users and 1 guest