[Eleanor Singer and Mick P. Couper, "Communicating Disclosure Risk in Informed Consent Statements," Journal of Empirical Research on Human Research Ethics 5, no. 3 (Sept. 2010): 1–8.]
Singer and Couper sent out more than 150,000 e-mails to get 9,206 responses to a questionnaire about willingness to participate in a hypothetical survey. Respondents were significantly more likely to say they'd be willing to answer questions about work and leisure than about the more sensitive topics of money and sex. In contrast,
the precise wording of the confidentiality assurance has little effect on respondents’ stated willingness to participate in the hypothetical survey described in the vignette. Nor does adding a statement on the organization’s history of assuring confidentiality appear to affect stated willingness. However, these experimental manipulations do have some effect on perceptions of the risks and benefits of participation, suggesting that they are processed by respondents. And, as we have found in our previous vignette studies—and replicated in a mail survey of the general population—the topic of the survey has a consistent and statistically significant effect on stated willingness to participate.
Singer and Couper hint that researchers and IRBs should spend less time fretting about the wording of consent forms used by survey researchers, since it does not affect decisions and since it is hard to estimate the risk of disclosure. Rather, the real burden on survey orgnizations is to take precautions once they have collected the data.