Evaluating Bias of Sequential Mixed-mode Designs Against Benchmark Surveys

This study evaluated three types of bias—total, measurement, and selection bias (SB)—in three sequential mixed-mode designs of the Dutch Crime Victimization Survey: telephone, mail, and web, where nonrespondents were followed up face-to-face (F2F). In the absence of true scores, all biases were estimated as mode effects against two different types of benchmarks. In the single-mode benchmark (SMB), effects were evaluated against a F2F reference survey. In an alternative analysis, a “hybrid-mode benchmark” (HMB) was used, where effects were evaluated against a mix of the measurements of a web survey and the SB of a F2F survey. A special reinterview design made available additional auxiliary data exploited in estimation for a range of survey variables. Depending on the SMB and HMB perspectives, a telephone, mail, or web design with a F2F follow-up (SMB) or a design involving only mail and/or web but not a F2F follow-up (HMB) is recommended based on the empirical findings.