Effects and costs of tracing strategies on nonresponse bias in a survey of workers with low-back injury

Declining rates of participation are an increasing challenge for studies that involve telephone surveys. This study examined the costs of a telephone survey methodology that used increasingly intensive tracing methods to track a pool of claimants who had sustained occupational back injuries. It also compared the respondent sample to people who refused the survey and/or were not located or contacted. 3,181 claimants were drawn from a database maintained by the Missouri Division of Workers' Compensation (DWC) and 1,475 completed a telephone interview. The DWC database provided data reflecting monetary and disability outcomes for all potential participants; telephone interviews provided additional self-reported data. More intensive tracing strategies improved the representativeness of the sample, yielding more women and minority participants. Relative to less intensive techniques, advanced tracing efforts located people whose DWC records were more similar to claimants not located. While the hands-on tracing efforts reduced the apparent bias of the respondent sample, costs increased as tracing strategies intensified - over $98,000 was spent to trace 1,027 claimants who were never located or contacted. The results suggest some guidelines that may facilitate decision-making for researchers and funders who must balance the trade-off between costs and nonresponse bias when planning surveys.