Notes on Permutation Tests for Spatial Cluster Detection with Censored Outcome Data

This short note evaluates the assumptions required for a permutation test to approximate the null distribution of the spatial scan statistic for censored outcomes proposed in Cook, Gold, and Li (2007, Biometrics 63, 540–549). In particular, we study the exchangeability conditions required for such a test under survival models. A simulation study is further performed to assess the impact on the type I error when the global exchangeability assumption is violated and to determine whether the permutation test still well approximates the null distribution.