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From | Sam Leary <S.D.Leary@bristol.ac.uk> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Relative survival - strel |
Date | Thu, 06 Oct 2011 11:07:26 +0100 |
death_5y = 1 if died by 5 years after diagnosis, 0 if still alive at 5 years age_diag = age at diagnosis (years) age_death = age at death or 5 years, whichever came first (years) I have downloaded a lifetable which has the following variables: country calendar_year sex age rateand I have only kept the data for the calendar year relating to the start date of my audit. I have also sorted this file by age then sex.
So I have used the following commands to calculate the crude and relative survival at 5 years after diagnosis:
stset age_death, failure(death_5y) origin(age_diag) strel 0 5 using "ltab_s1",mergeby(sex)My question is, as there are 257 deaths out of a total of 468, why is the crude survival percentage 41.86 using strel, rather than (468-257)/468 = 45.1?
Many thanks, Sam. ---------------------- Dr Sam Leary Senior Lecturer in Statistics Working hours: Monday, Tuesday and Thursday 7.30am - 2.30pm Lifecourse Epidemiology and Population Oral Health Research Group Department of Oral and Dental Sciences Bristol Dental School Lower Maudlin Street Bristol BS1 2LY Tel 0117 342 3264 Fax 0117 342 4443 E-Mail: S.D.Leary@bristol.ac.uk * * 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/