Interviews Hardest-to-Obtain in an Urban Health Survey

Survey researchers are necessarily concerned about possible bias in their survey data resulting from inability to interview all persons selected by the sampling plan. The proportion of persons in the sample with a particular socioeconomic characteristic, for example, may be underor overrepresented among those interviewed. Measuring bias caused by nonresponse is the responsibility of the statistician. The staff of the Master Sample Survey in the Washington Heights Health District undertook to study nonresponse bias by investigating the characteristics of a hard-to-obtain subsample.