Estimation of exponential survival probabilities with concomitant information.

Concomitant information on a l)atient's condition often accompanies survival time information. This paper presents a method of estimating survival distributions when the survival times are asstumed to follow simple exponential distributions, with a different parameter for eacli patient. The parameter associated with each patient's distribution is functionially related to the concomitant variates. The parameters are estimated by the method of maximum likelihood. An illustration of the method using acute leukemia survival data is given.