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Re: st: stcox: negative HR when used in bootstrap


From   Michael McCulloch <mm@pinest.org>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: stcox: negative HR when used in bootstrap
Date   Tue, 7 Aug 2007 16:14:49 -0700

Works just fine!
Thank you kindly.
Michael

bootstrap, reps(100): boot_hr

should be

bootstrap drug=r(drug), reps(100): boot_hr

Hope this helps,
Maarten

--- Michael McCulloch <mm@pinest.org> wrote:

 Hello,
 I'm puzzling over why the same stcox argument would return a negative

 HR value when bootstrapped. Any comments or critique would be
 welcomed!

 *--------------- begin code in question -----------------------

 sysuse cancer, clear
 stset studytim, failure(died)
 stcox drug

 sysuse cancer, clear
 stset studytim, failure(died)
 capture program drop boot_hr
	program define boot_hr, rclass

	* cox
	stcox drug
	indeplist, local
	foreach var of varlist `X' {
		return scalar `var' = exp(_b[`var'])
	}

 end
 set seed 12358
 bootstrap, reps(100): boot_hr
 *--------------- end code in question -----------------------

 --

 Michael McCulloch
 Pine Street Foundation
 124 Pine St., San Anselmo, CA 94960-2674
 Tel:	(415) 407-1357
 Fax:	(415) 485-1065
 mcculloch@pinestreetfoundation.org
 *
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-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands

visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434

+31 20 5986715

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


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