R help - Jul 2012 - Using pspline in bic.surv of BMA package

Hi,

I'm trying to using pspline in bic.surv{BMA}.

#############################
library(BMA)
library(survival)
data(veteran)
test.bic.surv<- bic.surv(Surv(time,status) ~
karno+pspline(age,df=3)+diagtime+prior, data = veteran, factor.type = TRUE)
summary(test.bic.surv, conditional=FALSE, digits=2)
#############################

The results are:

---------------------------------------------

Call:
bic.surv.formula(f = Surv(time, status) ~ karno + pspline(age,     df = 3) +
diagtime + prior, data = veteran, factor.type = TRUE)


  24  models were selected
Best  5  models (cumulative posterior probability =  0.59 ):

                        p!=0    EV       SD      model 1  model 2  model 3 
model 4  model 5
karno                   100.0  -3.3e-02  0.0051   -0.033   -0.032   -0.034  
-0.033   -0.033
pspline.age..df...3.1     9.3   9.3e-02  0.3678      .        .      1.068     
.        .
pspline.age..df...3.2     5.0   1.6e-02  0.1280      .        .        .       
.      0.368
pspline.age..df...3.3     4.3  -1.6e-04  0.1126      .        .        .       
.        .
pspline.age..df...3.4    37.4  -3.5e-01  0.5445      .     -0.917      .       
.        .
pspline.age..df...3.5     4.3  -5.9e-03  0.1028      .        .        .       
.        .
pspline.age..df...3.6     5.2   9.1e-03  0.0968      .        .        .     
0.287      .
pspline.age..df...3.7     4.7  -7.5e-03  0.0983      .        .        .       
.        .
pspline.age..df...3.8     4.4   2.0e-02  0.2562      .        .        .       
.        .
pspline.age..df...3.9     4.4  -1.9e-02  0.2490      .        .        .       
.        .
pspline.age..df...3.10    4.4  -8.2e-02  1.0178      .        .        .       
.        .
diagtime                  4.1   5.5e-05  0.0017      .        .        .       
.        .
prior                     4.2  -3.1e-05  0.0043      .        .        .       
.        .

nVar                                                 1        2        2       
2        2
BIC                                              -36.774  -35.832  -33.814 
-32.651  -32.498
post prob                                          0.281    0.176    0.064   
0.036    0.033
--------------------------------------------------

However, each column of basis matrix of age is treated as individual covariate
and BMA doesn't answer the question what's the probability of age being
included in the model.


I wonder if the bic.surv could provide the overall posterior probability for
each spline variable (similar to factor variables whose overall PMP is given).



Thanks you very much for your help!

Hui Xiong






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