Experimental Evidence to Optimize Linkage and Panel Consent Rates in a New Online Panel
This paper reports on four experiments aimed at optimizing both linkage and panel consent within the first wave of the new “Online Panel for Labour Market Research” (OPAL) in Germany, which comprised about 19,000 interviews. To improve linkage consent, the first question was placed at the beginning of the questionnaire. After the request for panel consent at the end of the interview, respondents who initially refused linkage were asked again for linkage consent. The framing (gain or loss) of these three requests was randomly varied.
The first request yielded a linkage consent rate of 84% to 85%, with no significant framing effects. The second request resulted in consent rates between 22% and 31%, indicating that about a quarter of respondents changed their mind after an additional request. Notably, loss framing resulted in a 6 percentage point increase in linkage consent for the second request. Overall, the cumulative linkage consent rate reached 88%.
The panel consent rate was approximately 62%, with no significant differences between the framing conditions. Multivariate results on the factors influencing both types of consent will be presented additionally.
In conclusion, the results of the experiments show that specific survey design features need to be taken into account when deciding whether a loss or gain framing is likely to be more effective in influencing respondents' consent decisions. In addition, this study also provides evidence that repeated requests minimize the proportion of initial linkage nonconsenters, leading to an increase in the cumulative linkage consent rate.