A binary-based approach for detecting irregularly shaped clusters

Abstract

BackgroundThere are many applications for spatial cluster detection and more detection methods have been proposed in recent years. Most cluster detection methods are efficient in detecting circular (or circular-like) clusters, but the methods which can detect irregular-shaped clusters usually require a lot of computing time.MethodsWe propose a new spatial detection algorithm for lattice data. The proposed method can be separated into two stages: the first stage determines the significant cells with unusual occurrences (i.e., individual clustering) by applying the Choynowski’s test, and the second stage determines if there are clusters based on the information of the first stage by a binomial approximate method. We first use computer simulation to evaluate the performance of the proposed method and compare it with the scan statistics. Furthermore, we take the Taiwan Cancer data in 2000 to illustrate the detection results of the scan statistics and the proposed method.ResultsThe simulation results support using the proposed method when the population sizes are large and the study regions are irregular. However, in general, the scan statistics still have better power in detecting clusters, especially when the population sizes are not large. For the analysis of cancer data, the scan statistics tend to spot more clusters, and the clusters’ shapes are close to circular (or elliptic). On the other hand, the proposed methods only find one cluster and cannot detect small-sized clusters.ConclusionsIn brief, the proposed methods can detect both circular and non-circular clusters well when the significant cells are correctly detected by the Choynowski’s method. In addition, the binomial-based method can handle the problem of multiple testing and save the computing time. On the other hand, both the circular and elliptical scan statistics have good power in detecting clusters, but tend to detect more clusters and have lower accuracy in detecting non-circular clusters.

Image Triplet

“…The method proposed by Wang and Yue (2013) first determines the significant cells with unusual occurrences by means of the Choynowski's test and then determines if there are clusters based on that information by a binomial approximate method. The simulation results support using the proposed method when the population sizes are large and the study regions are irregular.…”

“…The techniques for the detection of irregular spatial clusters presented here have numerous applications in a wide range of fields. The delineation of spatial clusters for a variety of chronic diseases (Wang and Yue 2013;Dematteï et al 2007;Kulldorff et al 2006;Duczmal et al 2007;Wan et al 2012) is an important tool of etiology, in order to assess their possible geographic related causes. A large area of application includes daily syndromic surveillance and disease surveillance.…”

Interoperability, XML Schema

“…The techniques for the detection of irregular spatial clusters presented here have numerous applications in a wide range of fields. The delineation of spatial clusters for a variety of chronic diseases (Wang and Yue 2013;Dematteï et al 2007;Kulldorff et al 2006;Duczmal et al 2007;Wan et al 2012) is an important tool of etiology, in order to assess their possible geographic related causes. A large area of application includes daily synsurveillance and disease surveillance.…”

Spatial scan statistics can be dangerous

“…Kulldorff et al 7 proposed an elliptic version of spatial scan statistic to deal with non-circular shaped clusters, but it is obviously insufficient. To detect arbitrarily shaped clusters that cannot be detected by circular spatial scan statistics, many authors [8][9][10][11][12][13][14][15][16][17][18] have proposed kind of sophisticated, but computationally quite intensive, spatial scan statistics. Among others, Tango and Takahashi 10 proposed a flexible spatial scan statistic along with FleXScan software 19 which has been evaluated as one of the most able to detect clusters of a rare disease.…”