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From |
"Kieran McCaul" <Kieran.McCaul@uwa.edu.au> |

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

Subject |
RE: st: "time ratios" and "hazard ratios" |

Date |
Fri, 15 May 2009 06:48:08 +0800 |

.. This one works: http://www.iser.essex.ac.uk/files/teaching/stephenj/ec968/pdfs/ec968lnotesv6.pdf ______________________________________________ Kieran McCaul MPH PhD WA Centre for Health & Ageing (M573) University of Western Australia Level 6, Ainslie House 48 Murray St Perth 6000 Phone: (08) 9224-2701 Fax: (08) 9224 8009 email: Kieran.McCaul@uwa.edu.au http://myprofile.cos.com/mccaul http://www.researcherid.com/rid/B-8751-2008 ______________________________________________ Epidemiology is so beautiful and provides such an important perspective on human life and death, but an incredible amount of rubbish is published. Richard Peto (2007) -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss Sent: Thursday, 14 May 2009 11:26 PM To: statalist@hsphsun2.harvard.edu Subject: AW: st: "time ratios" and "hazard ratios" <> The link to the book does not do much good for me. Is there an alternative? HTH Martin -----Ursprüngliche Nachricht----- Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von sjsamuels@gmail.com Gesendet: Donnerstag, 14. Mai 2009 16:58 An: statalist@hsphsun2.harvard.edu Betreff: Re: st: "time ratios" and "hazard ratios" -- "can I take the multiplicative inverse of the time ratio and report it as a hazard ratio?" No, The (log) Weibull is the only probability distribution for which this is true. It's a good idea to consider multiple probability distributions, as you have done. but reporting the regression results is not enough. Have you evidence that these distributions fit the data? (using a -linktest- or diagnostic plots, for example); that one fits any better or worse than the others? You can compare directly the likelihoods of the log-logistic and log-normal, and those of the log-normal and Weibull models. For hazard ratio models, I rarely see anything but a Cox model these days, because the Weibull has a very restrictive shape. Patrick Royston's -stpm- (from SSC) offers a flexible parametric version. For the log-linear regression models , the generalized Gamma in Stata has the most flexible shape, and its likelihood can be compared directly to those of the Weibull and log-normal. See: Stephen Jenkins's book "Survival Analysis", available from his website (http://www.iser.essex.ac.uk/teaching/degree/stephenj/ec968/pdfs/ec968lnotes v6.pdf ). -Steve On Wed, May 13, 2009 at 7:16 PM, Emory Morrison <Morrison@soc.msstate.edu> wrote: > I am reporting different specifications of event history models within the same paper. > > In some of the models (for example the log logistic specification and the log normal specification) stata reports coefficients as time ratios. > > In the Weibull model stata report coefficients as hazard ratios. > > While the direction of effects are clearly inverted in these two ways of reporting the coefficients, I need to know if these coefficients are precisely inverse. In other words, can I take the multiplicative inverse of the time ratio and report it as a hazard ratio? > > It would be very helpful in writing up the results of the paper, if the coefficients could be read and interpreted in a standardized fashion. > * * 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/ * * 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/ * * 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/

**References**:**st: "time ratios" and "hazard ratios"***From:*"Emory Morrison" <Morrison@soc.msstate.edu>

**Re: st: "time ratios" and "hazard ratios"***From:*sjsamuels@gmail.com

**AW: st: "time ratios" and "hazard ratios"***From:*"Martin Weiss" <martin.weiss1@gmx.de>

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