Capi, or Not Capi- That Is the Question: Using Administratative Data to Assign the Optimal Mode for Maximizing Response-Rates in a Household Panel

Background: Selecting the appropriate mode(s) of data collection is a major consideration for every survey. Personal interviews (CAPI) – typically recognized as the gold standard of data collection in surveys – have been increasingly called into question as the be-all and end-all of data collection methods, with a growing shift towards self-administered modes, particularly web surveys (CAWI). Reasons for this range from representation concerns due to shifting mode preferences and the flexibility these modes offer to busy respondents, all the way to practical constraints like health and safety concerns, interviewer availability, and budgetary restrictions. Yet, recruitment using CAWI alone might result in biases due to, e.g., systematic differences in digital skills. Thus, many surveys employ mixed-mode designs, raising the question of how to determine which mode should be offered to whom.

Data: The Austrian Socio-Economic Panel (ASEP), a household panel of the Austrian population, experimentally tested a tailored mode-design using administrative data to assign half of the sample’s households to their presumably preferred mode (CAPI/CAWI) while also offering the other mode after persistent non-response. The other households were randomly assigned to one of the mode-designs (CAPI-First/CAWI-First) as control groups.

Methods: To evaluate the utility of the tailored mode-design concept, we employed a multi-facetted analytical approach by comparing a variety of indicators, such as the rate of proxy-interviews, the number of requested mode-changes, or the overall response-rates and resulting nonresponse bias, between the different mode-designs.

Results: Results were promising regarding the tailored mode-design. For example, response-rates were consistently higher compared to the other mode-designs, while proxy-rates and the nonresponse bias were considerably lower.

Conclusion: With the tailored mode-design, we present an interesting and promising alternative to already established single- or mixed-mode designs. This novel approach could prove helpful to decrease nonresponse bias and survey costs while maintaining data quality.