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From | "JVerkuilen (Gmail)" <jvverkuilen@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: xtlogit: panel data transformation's recast to double makes model incomputable |
Date | Wed, 3 Apr 2013 01:05:06 -0400 |
On Tue, Apr 2, 2013 at 6:51 PM, Tom <tommedema@gmail.com> wrote: > Dear Jay, > > At first I thought that the problem may indeed be related to near > perfect prediction, but this would only be possible with a very small > sample size (it is not possible to perfectly predict prices with large > samples). Therefore I looked if any of the groups had a small number > of observations, and indeed there were a few due to some missing > values. I removed these such that every group now has at least 250 > observations, but the issue remains and seems to be exactly the same. > Therefore I do not think this is related to "near perfect prediction > issues". I'm not convinced that this is wrong, but you've looked at it so it makes sense to look elsewhere. > > For completeness, this is a log of the (still running) regression > showing that it cannot compute: > http://pastebin.com/Pe2PYTXw > > I'm still getting such messages: > log likelihood = -1.#INF > (initial step bad) Yeah that's clearly bad and not going to work. > What else can I try or what other information can I provide? The > methods I know on finding leverage points require me to actually get > the regression/estimation results. What approach do you suggest, > considering that I cannot get the results? Leverage is entirely about the X matrix so you can simply use regress and ask for the leverages in postestimation. Mind you I'm not super confident I'm correct, but it's something to look at. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/