“…The situation of no concomitant information, = 0 in (3), is covered in References [5,7], while the parametric concomitant formulation, (6), is treated in Reference [1,Chapter 12]. We can, with a slight modiÿcation, also approach the problem of estimating the log relative potency parameter, , as the second stage of a two-stage problem in the semi-parametric setting as well.…”