Re: [Gretl-users] GUI points
On Sat, 12 Nov 2016, Allin Cottrell wrote:
> While we're on the subject of the condition number and
collinearity, I have
> a question about the following example: Open the example data hall.gdt and
> select the two variables "consrat" and "ewr"; the correlation
output
> (again, right-click and then select from the context menu) then shows a
> corr coeff of just 0.16. The new collinearity analysis gives a whopping
> 634, an order of magnitude greater than the rule-of-thumb value 50. The
> bkw.gfn package confirms this value.
> This strikes me as qualitatively very different, and spontaneously I'm not
> sure why that is so. Any ideas?
The Pearson correlation coefficient is undefined if one or both of the terms
are constants. However, the Belsley condition number can handle a constant,
and presumably the big condition number in the example you describe (but
note, only when you include a constant) is due to the fact that consrat
itself is almost a constant. So these are rather different calculations
(although certainly related), and I'd rather keep them distinct.
While we're on the subject of GUI re-organisation: I too, like Stefano and
others, think that the proposed changes to the Model window menu structure
would be beneficial.
On the context menu idea, instead, I have a different view. Although it's
really nice to have frequently used actions just a click away, everyone's
got their favourites, and a right-click menu should not be overpopulated
IMO. OTOH, I wouldn't be averse to a slight reorganisation of the main
menu: we now have a "Variable" top-level entry which contains a selection
of things that you can do with a variable; logic would dictate that you
would have a parallel "List" entry with actions that you can perform with
a list. These, at the moment, are either inaccessible from menus (ie
add/drop variables from a list) or put into other places (ie View or Add).
So you would have a "Variables" menu with certain sub-entries like
"Graph", "Transform", "Analyze" etc and a parallel top-menu
"Lists" entry
with more or less the same structure. In this context, perhaps the "View"
menu could be disposed of.
I realise that maybe we're too close to release time to raise this point
now, but still, it would be nice to discuss ideas.
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Riccardo (Jack) Lucchetti
Dipartimento di Scienze Economiche e Sociali (DiSES)
Università Politecnica delle Marche
(formerly known as Università di Ancona)
r.lucchetti(a)univpm.it
http://www2.econ.univpm.it/servizi/hpp/lucchetti
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