The logarithm of the conditional hazard function of a survival time gi
ven one or more covariates is approximated by a function having the fo
rm of a specified sum of functions of at most d of the variables. Subj
ect to this form, the approximation is chosen to maximize the expected
conditional log-likelihood. Maximum likelihood and sums of tenser pro
ducts of polynomial splines are used to construct an estimate of this
approximation based on a random sample. The components of this estimat
e possess a rate of convergence that depends only on d and a suitably
defined smoothness parameter.