title: A qualitative discrepancy between censored data rank tests.
abstract: Two popular censored data rank tests were used to compare cancer incidence rates between dogs receiving bone marrow transplantation and control dogs. The logrank test gave a significance level of 0.01. In contrast, Gehan's generalized Wilcoxon test gave a significance level of 0.76. The statistics are displayed in a manner that shows how such contrasting significance levels can arise. The Gehan statistic is shown to be subject to a serious criticism that does not apply to other Wilcoxon generalizations. Further insight into the data is obtained using a time-dependent logrank test and the proportional hazards regression model.
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D004285:Dogs; D009374:Neoplasms, Experimental / Q000453:epidemiology* / Q000401:mortality / Q000532:radiotherapy; D013223:Statistics as Topic; D013997:Time Factors