A Test to Detect Clusters of Disease
提出一种检验统计量，通过病例间平均距离检测疾病发病率或死亡率数据的聚集性，并推导其零假设下的均值和方差及渐近正态性，适用于不同人口亚群风险差异的情况。
A test is given to detect clustering in disease incidence or mortality data The test statistic is the mean distance between all pairs of disease cases. Its null mean and variance and its asymptotic normality are derived under assumptions that accommodate differences in population distribution among demographic subgroups at different disease risk. The test is illustrated on 63 cases of anal and rectal squamous cell carcinoma in San Francisco during 1973–1981.