Don′t spin the pen: two alternative methods for second-stage sampling in urban cluster surveys
Don′t spin the pen: two alternative methods for second-stage sampling in urban cluster surveys
复制标题
DOI：
10.1186/1742-7622-4-8
复制
发表时间：
2007-06-01
影响因子：
2.3
通讯作者：
Guthmann, Jean-Paul
中科院分区：
文献类型：
--
作者：
Grais, Rebecca F.;Rose, Angela M. C.;Guthmann, Jean-Paul
在两阶段集群调查中，第二阶段抽样（选择集群中的第一个家庭）使用的传统方法耗时，并且可能导致对感兴趣指标的估计有偏差。首先，通常通过旋转笔来选择从聚类中心的随机方向。然后，沿着该方向沿着的房屋被计算到集群的边界，然后随机选择一个作为第一个被调查的家庭。这个过程有利于家庭向集群的中心，但它可以很容易地得到改善。最近在尼日尔马拉迪进行的脑膜炎疫苗接种覆盖率调查中，我们将这种第一家庭选择方法与城市地区的两种选择方法进行了比较：1）在集群区域的地图上使用叠加网格并随机选择一个交叉点; 2）使用全球定位系统（GPS）绘制集群区域的周边并随机选择周边内的一个点。虽然我们只比较了有限数量的集群使用每种方法，我们发现采样网格方法是最快和最简单的实地调查队，虽然它确实需要该地区的地图。还发现，一旦能够提供充分的培训，随机选择一个全球定位系统点也是一个好方法。转笔和数户到界是最复杂和耗时的。这里测试的两种方法代表了更简单，更快，可能更强大的替代旋转笔在城市地区的聚类调查。然而，在农村地区，这些替代方案将有利于从低密度（甚至可能是空的）地区进行最初的家庭选择。考虑到这些限制以及现有资源和可行性，调查人员应选择最适合其特定调查背景的方法。
In two-stage cluster surveys, the traditional method used in second-stage sampling (in which the first household in a cluster is selected) is time-consuming and may result in biased estimates of the indicator of interest. Firstly, a random direction from the center of the cluster is selected, usually by spinning a pen. The houses along that direction are then counted out to the boundary of the cluster, and one is then selected at random to be the first household surveyed. This process favors households towards the center of the cluster, but it could easily be improved. During a recent meningitis vaccination coverage survey in Maradi, Niger, we compared this method of first household selection to two alternatives in urban zones: 1) using a superimposed grid on the map of the cluster area and randomly selecting an intersection; and 2) drawing the perimeter of the cluster area using a Global Positioning System (GPS) and randomly selecting one point within the perimeter. Although we only compared a limited number of clusters using each method, we found the sampling grid method to be the fastest and easiest for field survey teams, although it does require a map of the area. Selecting a random GPS point was also found to be a good method, once adequate training can be provided. Spinning the pen and counting households to the boundary was the most complicated and time-consuming. The two methods tested here represent simpler, quicker and potentially more robust alternatives to spinning the pen for cluster surveys in urban areas. However, in rural areas, these alternatives would favor initial household selection from lower density (or even potentially empty) areas. Bearing in mind these limitations, as well as available resources and feasibility, investigators should choose the most appropriate method for their particular survey context.