Am 14.01.2013 15:33, schrieb Allin Cottrell:
On Sat, 12 Jan 2013, Andreas Noack Jensen wrote:
> When I extract the p-values from coint2 with restricted exogenous variables
> I receive a warning and a column of nans
>
> ? coint2 4 endo; d_IAU; IAU --crt --silent
> ? eval $pvalue
> 0,021269 nan
> 0,88179 nan
> 0,68159 nan
>
> Warning: generated non-finite values
>
> Is this intended? Can I suppress the warning?
The documentation, and probably the output, could do with some
improvement here.
Here's the current situation. The $pvalue accessor is set up
to provide an n x 2 matrix, where n is the number of
potentially cointegrated series. The first column contains
p-values for the trace test and the second contains p-values
for the lambda-max test. In the case of "partial systems",
where the analysis is conditional on one or more I(1)
variables, we can use the method of Harbo, Johansen, Nielsen
and Rahbek to get asymptotic p-values for the trace test but
so far as I'm aware there isn't a standard method for
obtaining p-values for the lambda-max test in this case. In
the printed output we show lambda-max p-values computed
"ignoring exogenous variables" but in the $pvalue matrix we
fill the second column with NaNs.
I can see two possible alternatives to current practice. We
could include in the $pvalue matrix the ("wrong") lambda-max
p-values that we print; or we could drop the second column for
the partial system case. Either way, of course, we should
clearly document what we're doing.
Or a third alternative: Maybe it could be useful to have a "warning
channel" also for scripting/accessor use, such that warnings such as
these also show up when you call the corresponding function. That would
make it possible to make the printed output and the accessor use
homogeneous.
Hope that was clear,
Sven