title: A spatial scan statistic for multiple clusters.
abstract: Spatial scan statistics are commonly used for geographical disease surveillance and cluster detection. While there are multiple clusters coexisting in the study area, they become difficult to detect because of clusters' shadowing effect to each other. The recently proposed sequential method showed its better power for detecting the second weaker cluster, but did not improve the ability of detecting the first stronger cluster which is more important than the second one. We propose a new extension of the spatial scan statistic which could be used to detect multiple clusters. Through constructing two or more clusters in the alternative hypothesis, our proposed method accounts for other coexisting clusters in the detecting and evaluating process. The performance of the proposed method is compared to the sequential method through an intensive simulation study, in which our proposed method shows better power in terms of both rejecting the null hypothesis and accurately detecting the coexisting clusters. In the real study of hand-foot-mouth disease data in Pingdu city, a true cluster town is successfully detected by our proposed method, which cannot be evaluated to be statistically significant by the standard method due to another cluster's shadowing effect.
authors.affiliation: State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China. lixz@lreis.ac.cn
authors.forename: Xiao-Zhou
authors.initials: XZ
authors.lastname: Li
authors.forename: Jin-Feng
authors.initials: JF
authors.lastname: Wang
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Yang
authors.forename: Zhong-Jie
authors.initials: ZJ
authors.lastname: Li
authors.forename: Sheng-Jie
authors.initials: SJ
authors.lastname: Lai
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004196:Disease Outbreaks; D005536:Foot-and-Mouth Disease / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D015233:Models, Statistical