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From |
sjsamuels@gmail.com |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: predictions after spsurv |

Date |
Thu, 19 Nov 2009 15:02:02 -0500 |

-spsurv- is by Stephen Jenkins, and it doesn't provide a -predict- option. One possible reason that a single prediction doesn't make sense with time-dependent predictors. I couldn't get -spsurv- to run the cancer example in its -help- without omitting the "drug" variable, but the results appear to be the same with and without version control. If you do not have time-dependent predictors, you can create your own predicted values (See 13.5 in the V11 User manual). For example, I ran the following command for the cancer data model in the -help file for -spsurv- spsurv dead logt age, id(id) seq(t) The linear predictor for time t is found by: x_t = hazard[_cons] + _b[logt]*logt _b[age]*age The discrete interval survival probability for interval t is: g_t = exp(-exp(x_t)) The probability s_T for survival up to time T for the non-cured part of the data is the product of the g_t for t<=T. It will probably be better to add the logs of the g's and then exponentiate. Finally the estimated probability of cure up to T is given by c + (1-c)*s_T c is in e(curep) or can be computed as exp([cure_p]_cons) The log(t) distribution form is very restrictive. Better, I think to group the data into larger intervals and estimate a separate parameter for each one, as Stephen recommends -Steve On Thu, Nov 19, 2009 at 12:03 PM, Mark S. Manger <m.s.manger@lse.ac.uk> wrote: > Thanks---and yes, spsurv (see sources below) is for Version 6/7. However, > > predict h, p > > still gives me the error "option p not allowed", so that's not the solution. > > Best, > > Mark > > > Reference: > > http://fmwww.bc.edu/repec/bocode/s/spsur_ll.ado > http://fmwww.bc.edu/repec/bocode/s/spsurv.ado > > > > Dr Mark S MANGER > Lecturer in International Political Economy > International Relations Department > London School of Economics > m.s.manger@lse.ac.uk > Phone +44 (0) 20 7955 6525 > > On 2009-11-18, at 19:59 , sjsamuels@gmail.com wrote: > >> -spsurv- is a user-written program, and the FAQ request that you note >> the source of such programs. >> >> From the -help- >> >> "spsurv works with Stata version 6 or version 7." >> >> I don't have Version 7 manuals any more, but I guess that the >> post-estimation commands were different. At best, you will have to >> run under version control. >> >> -Steve >> >> On Wed, Nov 18, 2009 at 1:08 PM, Mark S. Manger <M.S.Manger@lse.ac.uk> wrote: >>> Hi, >>> >>> I'm using spsurv to estimate a split-population survival model, and I'm trying to obtain some predictions to generate hazard functions graphs. >>> >>> Unfortunately, predict h, b doesn't work: "option p not allowed" and the default prediction is clearly not the probability. Can someone enlighten me how I can obtain a prediction of the probability? >>> >>> >>> Cheers, >>> >>> Mark >>> >>> >>> Stata 9.2 >>> OS X >>> >>> Dr Mark S MANGER >>> Lecturer in International Political Economy >>> International Relations Department >>> London School of Economics >>> m.s.manger@lse.ac.uk >>> Phone +44 (0) 20 7955 6525 >>> >>> >>> Please access the attached hyperlink for an important electronic communications disclaimer: http://www.lse.ac.uk/collections/secretariat/legal/disclaimer.htm >>> >>> * >>> * 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/ >>> >> >> >> >> -- >> Steven Samuels >> sjsamuels@gmail.com >> 18 Cantine's Island >> Saugerties NY 12477 >> USA >> 845-246-0774 >> >> * >> * 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/ > > > Please access the attached hyperlink for an important electronic communications disclaimer: http://www.lse.ac.uk/collections/secretariat/legal/disclaimer.htm > > * > * 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/ > -- Steven Samuels sjsamuels@gmail.com 18 Cantine's Island Saugerties NY 12477 USA 845-246-0774 * * 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: predictions after spsurv***From:*"Mark S. Manger" <M.S.Manger@lse.ac.uk>

**Re: st: predictions after spsurv***From:*sjsamuels@gmail.com

**Re: st: predictions after spsurv***From:*"Mark S. Manger" <m.s.manger@lse.ac.uk>

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