1) I think you will find that
vecm 1 1 Z2 Z1 --rc
estimates your system very well. I dont see the problem.
2) Consider simulating the model in VECM format. Otherwise I see no
problem with your approach.
3) If the series are not cointegrated then the residuals from the
cointegrating regression may have a stochastic trend -- thus the
specification of the test. Hayashi has a very good account of the
Engle Granger cointegration test.
4) To estimate a vecm one must have determined in advance fro testing
and/or economics the number of cointegrating relationships (or a least
a range for that number). I would not attach any priority to
programming the maximum number. In the version on my PC if I try to
enter to large a number of cointegating vectors I get a message
telling me that I have done so and I must correct it before I can
proceed.
Best Regards
John
On 7 March 2012 14:56, Talha Yalta <talhayalta(a)gmail.com> wrote:
Hi all,
I have a few questions/issues to report with a cointegration example
that I am trying to simulate using:
nulldata 500
setobs 1 1950 --time-series
series u1 = randgen(N,0,1)
series u2 = randgen(N,0,1)
series Z1 = 0
series Z1 = Z1(-1) + u1
series Z2 = 75 + 0.75*Z1 + u2
1)- When I run a VECM model afterwards, I always have one of the
inverse roots on the edge. Am I doing something wrong?
2)- Is there a better way of creating cointegrated series where I can
also set the EC coefficients (and/or the lag order)?
3)- Running the EG test, I notice that if the original series are
tested with a constant and/or a trend, the residuals in the 4th step
are also tested with a constant and/or trend. Can this be a bug, since
we are testing residuals?
4)- In the VECM specification window, one can choose up to 10
cointegrating vectors even if there are 2 series. IMHO, it would be
nice to put a limit depending on the number of series.
Thanks very much in advance for any help or suggestions.
Cheers
Talha
--
“An expert is a person who has made all the mistakes that can be made
in a very narrow field.” - Niels Bohr (1885-1962)
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John C Frain
Economics Department
Trinity College Dublin
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