It seems to me that summary for ridge coxph() prints summary but returns NULL.
It is not a big issue because one can calculate statistics directly from a
coxph.object. However, for some reason the score test is not calculated for
ridge coxph(), i.e score nor rscore components are not included in the coxph
object when ridge is specified. Please find the code below. I use 2.9.2 R with
2.35-4 version of the survival package. Thanks DK.
> fit <- coxph(Surv(futime, fustat) ~ ridge(rx, age, ecog.ps,
> theta=1),data=ovarian)
> a<-summary(fit)
Call:
coxph(formula = Surv(futime, fustat) ~ ridge(rx, age, ecog.ps,
theta = 1), data = ovarian)
n= 26
coef se(coef) se2 Chisq DF p
ridge(rx) -0.780 0.5862 0.5589 1.77 1 0.1800
ridge(age) 0.123 0.0387 0.0356 10.15 1 0.0014
ridge(ecog.ps) 0.104 0.5729 0.5478 0.03 1 0.8600
exp(coef) exp(-coef) lower .95 upper .95
ridge(rx) 0.459 2.181 0.145 1.45
ridge(age) 1.131 0.884 1.049 1.22
ridge(ecog.ps) 1.110 0.901 0.361 3.41
Iterations: 1 outer, 4 Newton-Raphson
Degrees of freedom for terms= 2.7
Rsquare= 0.452 (max possible= 0.932 )
Likelihood ratio test= 15.6 on 2.67 df, p=0.000941
Wald test = 12.9 on 2.67 df, p=0.00354
> a
NULL
> names(fit)
[1] "coefficients" "var" "var2" "loglik"
"iter" "linear.predictors" "residuals"
[8] "means" "method" "df" "df2"
"penalty" "pterms" "assign2"
[15] "history" "coxlist2" "printfun" "n"
"terms" "assign" "wald.test"
[22] "y" "formula" "call"
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
