Response and nonresponse bias in oral health surveys

Oral health surveys are undertaken to provide estimates of the dental healt h and behaviors of populations or population subgroups. However, the integr ity of the data from sample surveys may be compromised by one or more sourc es of sampling and nonsampling error. An important source of nonsampling er ror is the failure to collect data from some of the individuals comprising the sample. Consequently, the response to a sample survey, and the directio n and magnitude of bias induced by nonresponse, need to be taken into accou nt when using estimates derived from sample surveys. Although the response rate to a survey is usually used as an indicator of the quality of the data it provides, nonresponse error is a function of nonresponse and the extent of differences in the characteristics of responders and nonresponders. Non response may be managed in two ways. The first is to reduce nonresponse to a minimum using response-enhancement strategies. The second is the post-sur vey adjustment of data using weighting or imputation techniques to produce estimates that correct for nonresponse. This paper discusses issues concern ing response and nonresponse bias in oral health surveys and provides guide lines on the management and reporting of nonresponse. It describes response -enhancement strategies to reduce noncontacts and refusals, sources of data to facilitate the comparison of responders and nonresponders, methods of a ssessing the degree of bias induced by nonresponse, techniques for producin g adjusted survey estimates and the assumptions on which these procedures a nd processes are based.