Multi-Mode Surveys

Multi-mode surveys (sometimes called “mixed-mode surveys”) involve collecting information from survey respondents using two or more modes and combining the responses for analysis. Multi-mode surveys have become increasing popular because of the rise of new modes of data collection, the impact of computer technology, and decreasing response rates to traditional survey modes (particularly telephone surveys). The development of new modes of data collection has expanded the methods available to survey researchers. Multi-mode survey designs are extremely flexible when various combinations of modes can be employed to adapt to the particular needs of each research study. Multi-mode surveys are often used to compensate for coverage biases of individual modes and to increase overall response rates. However, these reductions in coverage and nonresponse must be balanced with potential increases in measurement error that may arise from combining responses collected using different modes.

Survey designs involve choosing the optimal mode or combination of modes while minimizing overall total survey error (coverage, sampling, nonresponse, and measurement). The decision of whether to use multiple modes for data collection involves several issues. Surveyors should consider the best mode or [Page 487]modes for the population and research of interest; some populations may not have access to a particular mode or may prefer to be surveyed by one mode, contact information may only be available for one mode of communication, and some questions or topics may lend themselves to a particular mode. Survey modes can be chosen to increase coverage of the population of interest (e.g. dual-sampling frame designs) and to minimize nonresponse bias resulting from differences between respondents and nonrespondents. Mode decisions are almost always influenced by the budget constraints of the particular study; often less expensive modes are used before more expensive modes to reduce overall data collection costs. Last, choices about survey mode are also guided by how quickly the data needs to be collected and whether the survey must be fielded within a particular time period.