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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: GLLAMM error: log-likelihood cannot be computed |

Date |
Mon, 8 Oct 2007 21:33:31 +0100 |

But I think the least unsatisfactory options are 1. To omit zeros and to indicate them by a rug of ticks on the other axis. 2. To plot downward-pointing arrows at say log(0.5). Whatever constant is used should be less than the smallest positive value observed. Nick n.j.cox@durham.ac.uk > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox > Sent: 08 October 2007 21:09 > To: statalist@hsphsun2.harvard.edu > Subject: RE: st: RE: GLLAMM error: log-likelihood cannot be computed > > > So, a log of 0 sometimes means that the data are 1 > and sometimes that they are 0? > > There's no neat solution to this one. > > Nick > n.j.cox@durham.ac.uk > > Leny Mathew > > > Thanks Nick. For the purposes of the graph, I created a new variable > > with the zeros changed to 1 and then took the log; > effectively setting > > them as zero in the log graph. I guess I could scale the > variable by a > > very small value and then take the log also. > > > > On 10/8/07, Nick Cox <n.j.cox@durham.ac.uk> wrote: > > > -gllamm- I leave to experts on it. > > > > > > -glm- produces predictions on the scale of the response, > > > whatever the link. It can also be quite sensible to use a > > > log scale for subsequent graphing. Indeed I've found > > > log link and log scale for graphs invaluable in some cases. > > > The results are not equivalent to transforming the response > > > because the log of the mean is not in general the mean > > > of the logs (and similarly for any nonlinear transformation). > > > > > > However, you can't show zeros on a log scale. If you > > > try this, Stata just gives you a dopey graph. That's > > > its way of saying "Isn't that rather a silly thing > > > to ask for?" * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: GLLAMM error: log-likelihood cannot be computed***From:*"Leny Mathew" <lenymathewc@gmail.com>

**References**:**RE: st: RE: GLLAMM error: log-likelihood cannot be computed***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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