[R] boot.stepAIC NA values
Martin McCabe
martin.mccabe at manchester.ac.uk
Fri Nov 5 16:33:26 CET 2010
Hi.
I have a coxph model of variables linked to survival in
medulloblastoma. The data were collated from various publications and
not all authors quoted all variables. I'd like to internally validate
the model and have tried bootstrapping it using boot.stepAIC but it
fails because of the NA values. If I remove all samples with any
missing values my dataset falls from n=227 to n=65 and, not-
surprisingly, only the most glaringly obvious variables remain in the
final model. Is there a way to get the boot-strapping and variable-
picking process to include samples with NA values, even though it's
not statistically the most correct approach?
Martin
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