Yoon S S, Katz J, Brendel K, West K P
National Center for Environmental Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30341-3724, USA.
Bull World Health Organ. 1997;75(5):417-26.
This study examines the efficiency of EPI cluster sampling in assessing the prevalence of diarrhoea and dysentery. A computer was used to simulate fieldwork carried out by a survey taker. The bias and variance of prevalence estimates obtained using EPI cluster sampling were compared with those obtained using simple random sampling and cluster (stratified random) sampling. Efficiency ratios, calculated as the mean square error divided by total distance travelled, were used to compare EPI cluster sampling to simple random sampling and standard cluster sampling. EPI cluster sampling may be an appropriate low-cost tool for monitoring trends in the prevalence of diarrhoea and dysentery over time. However, it should be used with caution when estimating the prevalence of diarrhoea at a single point in time because of the bias associated with this cluster sampling method.
本研究考察了扩大免疫规划（EPI）整群抽样在评估腹泻和痢疾患病率方面的效率。使用计算机模拟调查员开展的实地调查。将使用EPI整群抽样获得的患病率估计值的偏差和方差与使用简单随机抽样和整群（分层随机）抽样获得的偏差和方差进行比较。效率比的计算方法是均方误差除以总行程距离，用于比较EPI整群抽样与简单随机抽样和标准整群抽样。EPI整群抽样可能是一种适用于长期监测腹泻和痢疾患病率趋势的低成本工具。然而，由于这种整群抽样方法存在偏差，在估计某一时刻的腹泻患病率时应谨慎使用。
