Dear R-users,

I know that a few people have asked whether survreg handles left-truncation
data and the reply that i have seen so far is that it does.

However, when I try to use survreg on left-truncated data, I got the
following  error message.

> survcs3<-survreg(Surv(start,end,status)~AG, data=DPONEcs3,
dist="exponential")

Error in survreg(Surv(start, end, status) ~ AG, data = DPONEcs3, dist =
"exponential") :
        Invalid survival type

Then i tried

> cc<-survreg(Surv(end,status)~AG, data=DPONEcs3, dist="exponential")

and it works perfectly fine.

May I know why survreg does not accept my left-truncated data? I used
similar set of data on coxph and it works fine

Many many thanks for your time and any comments given


kind regards,
sing yee

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