Sampling a Rare and Mobile Population
*Karol Krotki, RTI International
Keywords: displaced population, sampling frame quality, field operations
RTI International designed and implemented a sample survey of the displaced population that resided in temporary trailers after the hurricanes Katrina and Rita in 2005. Targeted sample elements were children who had lived in the trailers even for a short period of time. CDC provided a list of families that had requested trailers but the list was several years old and had problems of accuracy and completeness. In this presentation we discuss the methodologies we developed to identify errors on the list, draw an efficient sample, and then to locate the identified sample elements. The sample was stratified geographically and by trailer type: group and individual. The group trailers in fact no longer exist, making it especially challenging to ensure good geographical stratification and to actually find the sampled units. This presentation will also discuss the extent to which field operations were successful in locating the units and the steps that had to be taken to find all sampled units. Finally, there is a control sample that matches the treatment (exposed) sample.