[R] Re : COXPH: how to get the score test and likelihood ratio test for a specific variable in a multivariate Coxph ?
Therneau, Terry M., Ph.D.
therneau at mayo.edu
Fri Jul 30 19:07:15 CEST 2010
The Wald, score, and LR tests are discussed in full in my book. They
are not the same.
The LR test is the difference between LR(beta=0) and LR(beta=final). The
score test is a Taylor series approximation to this using an expansion
around beta=0. The Wald test is a similar Taylor series approximation,
but around beta=final.
If there are no tied times the score test = Log-rank test. If there
are ties, then they are just a tiny bit different: the paper using the
log-rank has an n-1 in his variance term and the Cox model has an n.
Neither is right or wrong, just a different choice.
Terry Therneau
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