2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/130928We consider estimation in a class of semiparametric transformation models for right--censored data. These models gained much attention in survival analysis; however, most authors consider only regression models derived from frailty distributions whose hazards are decreasing. This paper considers estimation in a more flexible class of models and proposes conditional rank M-estimators for estimation of the Euclidean component of the model.Published at http://dx.doi.org/10.1214/074921706000000437 in the IMS Lecture Notes--Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org)Statistics Theory62G08 (Primary) 62G20 (Secondary)text