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From |
Nick Cox <njcoxstata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: goodness of fit measure fir ivtobit |

Date |
Mon, 24 Sep 2012 17:26:02 +0100 |

That is a puzzling argument, if indeed it's an argument at all. I don't think anything much in statistics ensures a _causal_ relationship (presumably what Yuval means here), short of independent evidence on mechanism or process. If a model is not that great, readers need to know. Sometimes a low R-squared makes that vivid. (People who want to remind me how limited R-squared is should please note that I wrote the FAQ cited below, which comes decorated with multiple warnings.) Nick On Mon, Sep 24, 2012 at 5:12 PM, Yuval Arbel <yuval.arbel@gmail.com> wrote: > Anat, note that the possibility to calculate the log likelihood is > there regardless of the method of estimation you are employing. > > In addition, I would personally rather avoid presenting an R-Squared > of 0.12, particularly in these kinds of models. As is well known, high > R-Squared does not ensure casual relationship and low R-Squared does > not ensure lack of casual relationship > > On Mon, Sep 24, 2012 at 4:54 PM, Anat (Manes) Tchetchik > <anatmanes@gmail.com> wrote: >> I haven't thought about the count model, I will definitely try to run >> it! thanks much! >> >> On Mon, Sep 24, 2012 at 5:38 PM, Maarten Buis <maartenlbuis@gmail.com> wrote: >>> That does not sound like censoring at all. I would think of this as a >>> regular count model. There are examples on how to deal with such an >>> iv-model in -help gmm-. >>> >>> Hope this helps, >>> Maarten >>> >>> On Mon, Sep 24, 2012 at 4:11 PM, Anat (Manes) Tchetchik >>> <anatmanes@gmail.com> wrote: >>>> Austin Hi, >>>> Thank you very much for your reply! >>>> What I have as a dependent var. are 500 respondents' reports of the >>>> number of times they travelled abroad to visit their friends and >>>> relatives over the course of their adult lives. Some respondents yet, >>>> who have relatives abroad, did not travel at all. >>>> So the observations are censored at zero, with mean =2.2, max =50 and >>>> stdev= 3.8. >>>> Do you think in that case that the general methods of moments will be better? >>>> Thanks much!!! >>>> Anat >>>> >>>> On Sun, Sep 23, 2012 at 5:49 AM, Austin Nichols <austinnichols@gmail.com> wrote: >>>>> >>>>> Anat (Manes) Tchetchik <anatmanes@gmail.com>: >>>>> You can always -predict- and compute the squared correlation of >>>>> predictions with observed values: >>>>> http://www.stata.com/support/faqs/statistics/r-squared/ >>>>> but are you sure your -ivtobit- model is justified? What is the >>>>> process that results in observations being censored? I suspect you >>>>> have a lower limit at zero which is actually a very low conditional >>>>> mean rounded down to zero--am I right? You may be better off with a >>>>> -gmm- model. >>>>> >>>>> On Sat, Sep 22, 2012 at 5:33 PM, Anat (Manes) Tchetchik >>>>> <anatmanes@gmail.com> wrote: >>>>> > Dear statalisters, >>>>> > >>>>> > I wonder if anyone knows any goodness of fit that is appropriate for >>>>> > tobit with endogenous >>>>> > variables (ivtobit). Not as in "regular" tobit, stata does not report any >>>>> > goodness of fit measure, any idea how to estimate such a measure? >>>>> > Any response will be greatly appreciated.. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: goodness of fit measure fir ivtobit***From:*Yuval Arbel <yuval.arbel@gmail.com>

**References**:**st: goodness of fit measure fir ivtobit***From:*"Anat (Manes) Tchetchik" <anatmanes@gmail.com>

**Re: st: goodness of fit measure fir ivtobit***From:*Austin Nichols <austinnichols@gmail.com>

**Re: st: goodness of fit measure fir ivtobit***From:*"Anat (Manes) Tchetchik" <anatmanes@gmail.com>

**Re: st: goodness of fit measure fir ivtobit***From:*Maarten Buis <maartenlbuis@gmail.com>

**Re: st: goodness of fit measure fir ivtobit***From:*"Anat (Manes) Tchetchik" <anatmanes@gmail.com>

**Re: st: goodness of fit measure fir ivtobit***From:*Yuval Arbel <yuval.arbel@gmail.com>

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