I don't know why Harrell's c is not available afert parametric survival model. However, it is definitely available after the -somersd- command, downloadable from SSC. If in Stata you type
somersd lifetime hazard, censtat(cstat) transf(c) tdist
and -lifetime- is a lifetime variable, -hazard- is a predictor of hazard rate, and -cstat- is a censorship status variable (positive for right-censored lifetimes, negative for left-censored lifetimes and zero for uncensored lifetimes), then you will get an estimate for Harrell's c, which is stored in e(b).
I hope this helps. Let me know if you have any further queries.
Best wishes
Roger
Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: [email protected]
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/
Opinions expressed are those of the author, not of the institution.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Andrzej Niemierko
Sent: 11 September 2009 14:46
To: Stata
Subject: st: stcrreg and Harrell's c index
Harrell's c index is not available as a postestimation statistic after
stcrreg (or any parametric survival model). Is there a theoretical reason
for this? If not, how can I compute it after stcrreg?
Andrzej
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