Professor Annette Jäckle, from the University of Essex is going to give a lecture as part of the LIfBi Lecture Series.
Previous studies have found that consent rates in online surveys are around 30 percentage points lower than those in face-to-face interviews. To date not much is known about why survey mode affects consent and what can be done to encourage informed consent without an interviewer.
This lecture reports on experiments with consent to link government tax records, conducted on the Innovation Panel (IP) of the UK Household Longitudinal Study. The IP is a probability sample of households in Great Britain, where all household members aged 16+ are interviewed annually.
The first study made use of the randomized allocation of sample households to mixed modes, either web-first or face-to-face first. We examined: To what extent does the survey mode affect consent outcomes, including consent rates, understanding of the consent request and confidence in the consent decision? Which mechanisms lead to differences in consent outcomes between modes? Does simplifying readability of the consent question reduce differences between modes in consent outcomes? Key findings include that the difference in consent rates is a causal effect of the mode on willingness to consent. Web respondents process the consent request less thoroughly and understand it less well when they answer online. Audio-recordings of the face-to-face interviews suggest that verbal behaviours of interviewers do not explain the mode effects: respondents only rarely ask questions or express concern, and interviewers only rarely offer additional information about the data linkage.
In a follow-up study we further examined the role of the interviewer in increasing consent rates. Does their presence lead to social pressures on the respondent to consent? Or does it lead to respondents making more effort in processing the request? To disentangle these mechanisms web respondents were randomly allocated to the control question wording, or to a version that included a photo and personal message from the survey director (to add an element of social pressure). The results were as expected, with the personal photo and message increasing consent rates compared to the control. Face-to-face respondents were randomly asked the consent question in CAPI, a computer assisted self-completion section (CASI), or a partial CASI where the question was read out by the interviewer but the respondent entered the answer in CASI (to remove any social pressure). The results from the CAPI-CASI experiment were, however, not as expected.