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On the fit of the NK model

PostPosted: Sat Jan 17, 2015 9:35 am
by aiq
Howdy!

I am trying to gauge the fit of the NK model by generating data, and comparing it to data sample used in the SW(2007) model.

I have the NK model (using the code available on this website nk.mod), which I run to get observations for inflation, output and interest rate (using the get_simul_replications.m code). Then I run a simple script (co.m) which uploads SW(2007) data, and the data generated by the nk model, and plots them. Then we can compare the two data sets. As you can see I get a terrible fit, which is surprising, as the data set is not even close to each other.

The data file usd contains the SW(2007) data for output,inflation and interest rate (transformed data used for estimation -dy,pin fobs,robs)

Can anyone comment? Appreciate it!

Re: On the fit of the NK model

PostPosted: Sat Jan 17, 2015 5:18 pm
by jpfeifer
For output growth, they are pretty similar. For the interest and inflation rate I am not sure you are comparing the same objects (net vs. gross; demeaned vs. undemeaned)

Re: On the fit of the NK model

PostPosted: Sat Jan 17, 2015 6:16 pm
by aiq
As always thank you for the reply.

I thought of that, but since I am using the measurement equations(from SW(2007)) and comparing it with the transformed data used in estimation (again from SW(2007)), I thought I'd get a pretty good fit, and won't have to worry about transformations and all that. Is their something fundamentally wrong with my approach/results?

Re: On the fit of the NK model

PostPosted: Sat Jan 17, 2015 6:31 pm
by jpfeifer
Using their observation equation to generate artificial observed variables does only work if the model variables used in the observation equation are the same. I haven't looked at the models to verify this.

Re: On the fit of the NK model

PostPosted: Sun Jan 18, 2015 1:57 pm
by aiq
Checked all that, still really bad fit...

Re: On the fit of the NK model

PostPosted: Sun Jan 18, 2015 2:58 pm
by jpfeifer
Where did you get the calibration from?

Re: On the fit of the NK model

PostPosted: Fri Oct 23, 2015 10:14 am
by aiq
From smets and waters (2007)

Re: On the fit of the NK model

PostPosted: Sat Oct 24, 2015 6:47 am
by jpfeifer
Then you need to check if their calibration is correct for your model. For example, Smets/Wouters have indexing in their model. Does yours as well?

Re: On the fit of the NK model

PostPosted: Sun Oct 25, 2015 4:20 pm
by aiq
Thanks, I think I figured it out. As always I am grateful for your opinions and comments!