The code below first generates a weibull ?model, then
uses predict to create a vector of the linear predictors, then
attempts to create the 'expected' vector, which is empty. ?The final
two steps in the code generate a lognormal model with the same data,
and the same empty 'expected' vector.
My expectation had been that 'expected' would generate the same
transformed dependent variable output as predict with a survreg model
using type='response'. ?Since my 'real' data is left-truncated and
right-censored I cannot use survreg, and I wanted to investigate the
output from eha.
Thanks in advance!
Mike
data(mort)
aftreg(Surv(enter, exit, event) ~ ses, data = mort)
Call:
aftreg(formula = Surv(enter, exit, event) ~ ses, data = mort)
Covariate ? ? ? ? ?W.mean ? ? ?Coef Exp(Coef) ?se(Coef) ? ?Wald p
ses
? ? ? ? ? lower ? ?0.416 ? ? 0 ? ? ? ? 1 ? ? ? ? ? (reference)
? ? ? ? ? upper ? ?0.584 ? ?-0.348 ? ? 0.706 ? ? 0.089 ? ? 0.000
log(scale) ? ? ? ? ? ? ? ? ? ?3.603 ? ?36.698 ? ? 0.065 ? ? 0.000
log(shape) ? ? ? ? ? ? ? ? ? ?0.331 ? ? 1.392 ? ? 0.058 ? ? 0.000
Events ? ? ? ? ? ? ? ? ? ?276
Total time at risk ? ? ? ? 17038
Max. log. likelihood ? ? ?-1391.3
LR test statistic ? ? ? ? 16.1
Degrees of freedom ? ? ? ?1
Overall p-value ? ? ? ? ? 5.91578e-05
m1 <- aftreg(Surv(enter, exit, event) ~ ses, data = mort)
head(predict(m1, type='lp')) ## produces output
? ? ? ?1 ? ? ? ? 2 ? ? ? ? 3 ? ? ? ? 4 ? ? ? ? 5 ? ? ? ? 6
-0.347853 ?0.000000 -0.347853 ?0.000000 ?0.000000 ?0.000000
head(predict(m1, type='expected')) ## is this correct?
m2 <- aftreg(Surv(enter, exit, event) ~ ses, dist='lognormal', data = mort)
head(predict(m2, type='expected')) ## is this correct?
numeric(0)
from eha (the survival and rms packages are not an option for my
'real' question, since I have left-truncated right-censored data