Special on Survey Methodology: What is the price of going fully online? A mixed-mode sampling experiment on the occasion of the Swiss general elections 2019

The FOKUS Aargau Mixed Mode Survey Experiment Survey-based research is currently in the process of moving partly or completely online. The scalability of online surveys not only helps to cut costs but also allows for a streamlined production of reporting which draws directly on the data. Data pre-processing can be cut to a minimum or be largely eliminated. Whereas current experience with online surveys in Switzerland shows good response rates, less is known about the quality of the sample in comparison to telephone or postal surveys. On the occasion of the October 2019 general elections in Switzerland, the FOKUS Aargau team at the ZDA therefore conducted an experiment evaluating how the response rate as well as the sample quality might differ in an online versus an offline survey. Based on the official address register, 10'000 randomly drawn residents of the Canton of Aargau who are also Swiss citizens received an invitation letter asking them to take part in the survey. While half of the sample received a paper version as well as a pre-paid envelope, giving them the option to submit their questionnaires by mail, the other half was directed to the address of the online survey with a provided link (or QR-code) only. Results The initial as well as total response rate among survey respondents who had the choice of either using the paper version and sending it in via pre-paid mail or using the online version was somewhat higher than for the sample in which the only available channel with which to respond was the internet. However, the difference in response rates between the two modes is not large and one might conclude that the paper mode is more or less obsolete. However, response rates are not the only criterion when evaluating the quality of a survey sample. With regard to representativeness the two sub-samples tend to complement each other. The sample with the mail-in option is more representative of gender, older age groups and people with a lower formal level of education. For the online sample the pattern is the reverse. In total, the mixed-mode samples, in combination, clearly yielded the most representative sample. Regarding over-reporting, there is no difference between the two survey modes. The most striking differences between respondents' answering mode are revealed when looking at the political preferences, which are crucial for a post-election survey. Mail-in survey respondents clearly tend to favor identifying and voting for the SVP (Swiss People's Party), online mode respondents more often vote for left-wing political parties. However, when controlling for other variables in a multi-variate model, party-based differences almost disappear and what emerges in its place is a pattern of digital divide, e.g. with respondents favoring the nationwide introduction of internet voting tending to opt for the online survey mode. In sum, consistent with other studies, we find that the exclusion of offline households produces significant coverage biases, while the inclusion of these households in the sample improves the representativeness of the survey significantly. Non-response as the last of the three quality criteria compared among the two survey modes showed stark differences. With a meagre completion rate of 52 percent, the paper version fares much worse than the online mode for this survey (84% completion)

Special zum Thema „E-Voting“

Zwei Drittel der Aargauer Stimmbevölkerung haben sich in einer Umfage Ende November 2018 positiv gegenüber der Einführung von E-Voting geäussert. Die Zustimmung zur Einführung eines digitalen Stimmkanals ist besonders stark ausgeprägt bei Befragten unter 60 Jahren. Neben dem Alter als erklärenden Faktor spielt unabhängig davon ein digitaler Lebensstil eine wichtige Rolle. Politische Eigenschaften sind im Vergleich weniger wichtig. Tendenziell geht jedoch eine konservativere Einstellung, wie sie etwa in der Annahme der Selbstbestimmungs-Initiative zum Ausdruck kommt, mit der Ablehnung von E-Voting einher