[R] Survival, Kaplan-Meier, left truncation

[Göran Broström]

On Wed, Jan 07, 2004 at 12:57:46PM +0100, Rau, Roland wrote:
> Dear all,
> 
> I have data from 1970 to 1990 for people above age 50.
> Now I want to calculate survival curves by age starting at age 50 using the
> Kaplan Meier Estimator.
> The problem I have is that there are already people in 1970 who are older
> than 50 years.
> I guess this is called delayed entry or left truncation (?).
> 
> I thought the code would be:
> 
> roland <- survfit(Surv(time=age.enter, time2=age.exit, event=status,
> type="interval")~1, weights=gewicht,
> 	type="kaplan-meier")

Not type = "interval", but "count" (or just leave it out)
You can also use 'plot.Surv' in package 'eha' (for plotting).

-- 
 Göran Broström                    tel: +46 90 786 5223
 Department of Statistics          fax: +46 90 786 6614
 Umeå University                   http://www.stat.umu.se/egna/gb/
 SE-90187 Umeå, Sweden             e-mail: gb at stat.umu.se