Dose–response model for cancer death estimation of the form \[P = 1 - \exp [-(q_{0} + q_{1}d_{1} + q_{2}d_{2} + \ldots + q_{k}d_{k})]\] where \(P\) is the probability of cancer death from a continuous dose rate, \(d_{i}\) , of group (or stage) \(i = 0, 1, 2 \ldots\), the \(q\)’s are constants, and \(k\) is the number of dose groups (or, if less than the number of dose groups, \(k\) is the number of biological stages believed to be required in the carcinogenesis process). With the multistage model, it is assumed that cancer is initiated by cell mutations in a finite series of steps.