The problem is that Stata is not considering in any way that there was a time
interval during which the subject was not at risk of failing. So it treats in
the same way an individual that failed, and wasn't at risk for a long time, and
then began a second period of risk than one that survived all that time.
JM
Quoting Chris Chung <[email protected]>:
> You don't want to reset the second risk set as 0 as you need to incorporate
> the history of the individuals that experienced the first event. Typically,
> event history models analyze the occurrence and timing of an event that may
> be experienced only once; the observed survival or failure times are assumed
> to be independent. However, in the multiple failure time data, observed
> failure times within the same individual cannot be assumed to be
> independent. Note that repeated event data are a special type of event
> history data, which records the timing of transitions between two or more
> discrete states. If you reset the second risk set as 0, you arbitrarily
> treat the individuals that experienced the first event and others which did
> not experience it (or have yet to experience it) the same. So, you better
> code them with sequential event numbers, rather than resetting to 0.
>
>
>
> Hope it helps,
>
> Chris Changwha Chung
>
>
>
>
>
> ----- Original Message -----
> From: "Juan Manuel Jauregui" <[email protected]>
> To: <[email protected]>
> Sent: Tuesday, April 25, 2006 2:59 PM
> Subject: Re: st: stset with multiple spells
>
>
> > Thank you so much, Chris. The paper you suggest is great. It's very long,
> > so I
> > couldn't read it in detail, but seems that it's going to help me a lot,
> > especially considering that it brings the codes. However, at least at
> > first
> > sight, it doesn't seem to help me with the issue of setting the analysis
> > time
> > to zero again when the individual enters the second period of time at
> > risk. I
> > mean, after the first failure, and a period of time of not being at risk.
> > Do
> > you know how can I do it?
> >
> > Thanks a lot.
> >
> > Juan
> >
> >
> >
> >
> > Quoting Chris Chung <[email protected]>:
> >
> >> Cleves' STB-49 should be a good place to start. You may also want to look
> >> at:
> >> Ezell, M.E., Land, K.C., & Cohen, L.E. 2003. Modeling multiple failure
> >> time
> >> data: A Survey of variance-corrected proportional hazards models with
> >> empirical applications to arrest data. Sociological Methodology, 33:
> >> 111-167.
> >>
> >> HTH,
> >> Chris
> >>
> >>
> >> ----- Original Message -----
> >> From: "Sara Mottram" <[email protected]>
> >> To: <[email protected]>
> >> Sent: Monday, April 24, 2006 2:57 AM
> >> Subject: Re: st: stset with multiple spells
> >>
> >>
> >> > Hi Juan,
> >> >
> >> > I think that I am trying to do a similar analysis where I look at the
> >> > number of consultations with a doctor for a certain condition, over a
> >> > three year period. You do not say which version of Stata you are using
> >> > but
> >> > I think this type of analysis is possible in Version 9 by considering
> >> > the
> >> > data as multiple failures. However, I haven't got any further than this
> >> > myself. I believe that exactly which command and options you need to
> >> > use
> >> > depends on the precise question. You might also want to look at the
> >> > paper
> >> > by Jos Twisk. "Twisk J, Smidt N, de Vente W. Applied analysis of
> >> > recurrent
> >> > events: a practical overview. J. Epidemiol. Community Health 2005;
> >> > 59;706-10". which can be found at
> >> > http://jech.bmjjournals.com/cgi/reprint/59/8/706.
> >> > Hope this helps and perhaps someone else could clarify the situation
> >> > further.
> >> >
> >> > Sara
> >> >
> >> >
> >> > Juan Manuel Jauregui wrote:
> >> >> My fellow Stata lovers,
> >> >>
> >> >> I'm trying to stset my dataset, and I'm having trouble. I already read
> >> >> the [st]
> >> >> manual, the great book by Cleves et al (2004) and also his excelent
> >> >> review of
> >> >> this issue at the FAQ (reproducing the STB-49) and even a search of
> >> >> the
> >> >> Statalist history and other websites wasn't fruitful.
> >> >>
> >> >> Here is my problem:
> >> >>
> >> >> I have an unbalanced panel of almost 200 individuals (countries in
> >> >> this
> >> >> case)
> >> >> with 100 records each (25 years of quarterly data) and I want to study
> >> >> the
> >> >> duration of some periods of financial distress. I have an event that
> >> >> marks the
> >> >> begining of each crisis, and another event that marks its end. This
> >> >> crises
> >> >> periods appear more than once for each country and they are separated
> >> >> from each
> >> >> other by periods of tranquility, that is, analysis time should begin
> >> >> from
> >> >> 0 when
> >> >> a new crisis begins.
> >> >>
> >> >> The closest thing I think I can do is to take each episode as an
> >> >> individual and
> >> >> take countries as groups and use a shared frialty model, but that
> >> >> wouldn't be
> >> >> exactly what I want to do. I'd prefer to take it as repeated episodes
> >> >> of
> >> >> the
> >> >> same individual.
> >> >>
> >> >> Any help will be greatly appreciated.
> >> >>
> >> >> Thanks a lot!
> >> >>
> >> >> Juan Manuel Jauregui
> >> >> Doctoral Student
> >> >> Global Economics and Management
> >> >> UCLA Anderson School of Management
> >> >> *
> >> >> * 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/
> >> >>
> >> >
> >> > --
> >> > Sara Mottram Research Assistant: Biostatistics
> >> > Primary Care Musculoskeletal Research Centre
> >> > Primary Care Sciences
> >> > Keele University
> >> > Staffordshire, ST5 5BG
> >> > Tel: 01782 584711
> >> > Fax: 01782 583911
> >> > *
> >> > * 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/
> >>
> >> *
> >> * 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/
> >>
> >
> >
> > *
> > * 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/
>
> *
> * 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/
>
*
* 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/
