Dear Martin,
You're most welcome!
As an addition to my yesterday's reply and related references (included the ones pointed out by Jose Maria Pacheco de Souza), I would kindly recommend you to take a thorough look Stata Manual [ST] Survival Analysis and Epidemiological Tables (my release is 9).
Kind Regards and All the Best for your research project,
Carlo
-----Messaggio originale-----
Da: Martin Wang [mailto:[email protected]]
Inviato: lunedì 3 novembre 2008 19.17
A: Carlo Lazzaro
Oggetto: Re: R: st: R: Someone help me on the multiple failure duration model?
Dear Carlo,
Many thanks indeed that you even tried to test the data! Your asnwer definitely helps a lot! From your procedure I have a basic idea of how to deal with such problems. I'd like to reconfirm one thing, that is, you see from my data, the key variable - health state, in some year did not change from the last year but the control variable (weight) changed. I'd like to make sure that there is no problem if I use all the observations (which I think is 18 observations in total).
Many thanks again!
Best,
Martin
======= 2008-11-04 01:43:04 Original Message：=======
>Dear Martin,
>I tried to load the excerpt of the data set provided in your previous message. Whereas Cox proportional hazard model seems to hold (please, see -estat phtest-), the Gamma generalized regression for finding which parametric survival model fits best with your data, doesn't converge (please, see the error message).
>
>stset year, id(id) failure(health_state==1) exit(time .) scale(1)
>
> id: id
> failure event: health_state == 1
>obs. time interval: (year[_n-1], year]
> exit on or before: time .
>
>------------------------------------------------------------------------------
> 21 total obs.
> 0 exclusions
>------------------------------------------------------------------------------
> 21 obs. remaining, representing
> 3 subjects
> 6 failures in multiple failure-per-subject data
> 21 total analysis time at risk, at risk from t = 0
> earliest observed entry t = 0
> last observed exit t = 7
>
>stcox female weight, schoenfeld(sch*)
>
> failure _d: health_state == 1
> analysis time _t: year
> exit on or before: time .
> id: id
>
>Iteration 0: log likelihood = -5.7807435
>Iteration 1: log likelihood = -4.7542542
>Iteration 2: log likelihood = -4.7462302
>Iteration 3: log likelihood = -4.746223
>Refining estimates:
>Iteration 0: log likelihood = -4.746223
>
>Cox regression -- no ties
>
>No. of subjects = 3 Number of obs = 18
>No. of failures = 6
>Time at risk = 18
> LR chi2(2) = 2.07
>Log likelihood = -4.746223 Prob > chi2 = 0.3554
>
>------------------------------------------------------------------------------
> _t | Haz. Ratio Std. Err. z P>|z| [95% Conf. Interval]
>-------------+----------------------------------------------------------------
> female | .2556673 .3192123 -1.09 0.275 .0221264 2.954196
> weight | 1.079909 .0695928 1.19 0.233 .9517721 1.225297
>------------------------------------------------------------------------------
>
>. estat phtest
>
> Test of proportional hazards assumption
>
> Time: Time
> ----------------------------------------------------------------
> | chi2 df Prob>chi2
> ------------+---------------------------------------------------
> global test | 2.77 2 0.2505
> ----------------------------------------------------------------
>
>streg female weight, dist(gamma)
>
> failure _d: health_state == 1
> analysis time _t: year
> exit on or before: time .
> id: id
><output omitted>
>discontinuous region encountered
>cannot compute an improvement
>r(430);
>
>I cannot rule out the occurrence of some mistakes in my tackling the issues you outlined.
>
>I do hope that it (at least a bit) help.
>
>Kind Regards,
>Carlo
>-----Messaggio originale-----
>Da: [email protected] [mailto:[email protected]] Per conto di Martin Wang
>Inviato: lunedì 3 novembre 2008 17.03
>A: [email protected]; [email protected]
>Oggetto: Re: st: R: Someone help me on the multiple failure duration model?
>
>Dear Carlo,
>
>Many thanks for your suggestion. I've just requested the book from other library. But my question is a little bit urgent, if anyone happens to know the answer could you please kindly help.
>
>Thanks!
>
>Martin
>
>======= 2008-11-03 23:40:52 Original Message：=======
>
>>Dear Martin,
>>all these topics are covered in Cleves MA, Gould WW, Gutierrez RG. An
>>introduction to survival analysis using Stata. Revised edition. College
>>Station: Stata Press, 2004.
>>
>>In my opinion, this is a very "good value for money" textbook.
>>
>>
>>Kind Regards,
>>
>>Carlo
>>-----Messaggio originale-----
>>Da: [email protected]
>>[mailto:[email protected]] Per conto di Martin Wang
>>Inviato: luned?3 novembre 2008 16.22
>>A: [email protected]
>>Oggetto: st: Someone help me on the multiple failure duration model?
>>
>>/********** This is a html email************************/
>>
>>Dear all,
>>
>>Can someone help me on the multiple failure duration model? For example,
>>let's say I have the following data:
>>
>>
>>year | 1 | 2 | 3 |
>>4 | 5 | 6 | 7
>>patient 1(Female)|weight:50,ill(0)| weight:52,ill(0) |
>>weight:53,fine(1)|weight:48,fine(1)|weight:50,ill(0) |weight:50,ill(0)
>>|weight:50,ill(0)
>>patient 2(male) |weight:51,ill(0)| weight:48,ill(0) | weight:60,ill(0) |
>>weight:67,ill(0)|weight:78,fine(1) |weight:60,fine(1)| (missing)
>>patient 3(male) |weight:52,ill(0)| weight:50,fine(1)| (missing) |
>>(missing) | weight:50,fine(1)| weight:40,ill(0)| weight:60,ill(0)
>>
>>
>>You see for each patient there are multiple observations, and also there may
>>be multiple failures(in this case - getting fine). And also some subject has
>>gap in the data, for example patient 3 has gap in year 3 and year 4. I
>>wonder whether I can still use streg or stcox for this setting and use ALL
>>the observations. For example,
>>
>>*****************************************************
>>stset t, id(patient) failure(fine) exit(time .) noshow
>>stcox weight female, r
>>or streg weight female, r
>>*****************************************************
>>Can anyone kindly help me out? Any suggestions?
>>
>>Many thanks!!
>>
>>Martin
>>
>>*
>>* 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/
= = = = = = = = = = = = = = = = = = = =
*
* For searches and help try:
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