Date:         Thu, 31 May 2001 09:11:50 -0700
Reply-To:     Cassell.David@EPAMAIL.EPA.GOV
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "David L. Cassell" <Cassell.David@EPAMAIL.EPA.GOV>
Subject:      Re: TIES=EFRON
Content-type: text/plain; charset=us-ascii

Anna Axmon wrote:
> could anyone tell me exactly what it is I do when I use TIES=EFRON in the
PROC PHREG?

It is a method for handling ties in the failure times.  It uses
the approximate likelihood method put forth in Efron, 1997, "The
efficiency of Cox's likelihood function for censored data",
Journal of the American Statistical Association, vol 72, pp. 557-565.

From the online docs:

The Efron likelihood is


Or maybe it means you have to wear one of Brad Efron's ties to get the
PROC to work right.  :-)
David
--
David Cassell, CSC
Cassell.David@epa.gov
Senior computing specialist
mathematical statistician