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From |
Steve Samuels <sjsamuels@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: intcens: how to estimate mean and variance after intcens |

Date |
Fri, 26 Oct 2012 00:17:12 -0400 |

Sorry, line wrapping garbled the command, which is: ********************************************************************** list _t date_left_censoring date_deb_periode1 if date_left_censoring>_t ********************************************************************* S. Without seeing your data, we cannot possibly diagnose your problem. I consider it a mistake to use scale(365.25): 365.25 is not a natural unit since no number of days will equal it. In any case, we need to see the original date values, so omit the scale() option from -stset-. Have you examined the sources of the message from Stata? [NB: not "STATA"] ************************************************* list _t date_left_censoring date_deb_periode1 if date_left_censoring>_t *************************************************** Do this after formatting all the listed values, including _t with %td. It's not necessary to run -stpm- to get this listing, as all values are available after -stset-. Steve On Oct 25, 2012, at 4:43 AM, Yoann Madec wrote: Thanks steve for your comments, and sorry not to have mention the source of the intcens command. After reading the help page for stpm, I still do not manage to make it work with interval-censored data. As a test, I have written: gen date_left_censoring=seroco_d stset date_deb_periode1, scale(365.25) origin(seroco_d) failure(hiv_controleur_bis) In this case, I should have no interval-censored data, but strictly right-censored data. However, here is what STATA states: . xi: stpm i.gender if num_v==1, stpmdf(6) scale(hazard) left(date_left_censoring) i.gender _Igender_1-2 (naturally coded; _Igender_1 omitted) date_left_censoring>_t in some observations I have been trying many things without success. I hope someone can help. Best regards, Yoann Le 12/10/2012 19:48, Steve Samuels a écrit : > > Yoann, The FAQ ask that you state the source of unofficial commands. > -intcens- was written by Jamie Griffin and is available from SSC. > > The usual sample descriptive statistics cannot be calculated for > interval-censored data. > > One approach is to apply Patrick Royston's command -stpm-, also at SSC, > which fits flexible distributions. You can estimate survival curves and > percentiles of the unconditional as well as covariate-conditional, > distributions. You won't get standard errors for the percentiles, but > you could -bootstrap- these. Means and SDs can be estimated with a lot > more work, but I don't think these are useful descriptive stats for > most survival data problems. > > In fact, I recommend -stpm-, not -intcens- for your main analysis. Some > reasons: 1) Both fit parametric models, but -stpm- adapts to the shape > of the distribution, saving you the need to select a "best" theoretical > distribution. 2) -stpm- has excellent postestimtion options; -intcens- > has none. (You can estimate survival curves& statistics starting with > the supplied e(b) matrix, but you must do it by hand.) 3) -stpm- allows > coefficients to vary with time (i.e. time-predictor interactions,); > -intcens- does not. > > > Steve > > > > On Oct 11, 2012, at 12:35 PM, Yoann Madec wrote: > > Dear Stata users, > > In order to describe the time to an event I used the command intcens. Indeed, for all my subjects, I know that the event took place within a time-interval, but do not have thje exact date. > > Using intcens, I vcan test whether some factors influence this time to event. > > However, I would like to summarize the time to event and provide a confidence interval for this time. > I have not been able to fin how to estimate a mean and variance after intcens. > > i hope that someone will be able to help. > > Best regards, > > Yoann > > * > * 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/ > > > * > * 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/ * * 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/

**References**:**st: intcens: how to estimate mean and variance after intcens***From:*Yoann Madec <yoann.madec@pasteur.fr>

**Re: st: intcens: how to estimate mean and variance after intcens***From:*Steve Samuels <sjsamuels@gmail.com>

**Re: st: intcens: how to estimate mean and variance after intcens***From:*Yoann Madec <yoann.madec@pasteur.fr>

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