he authors of an IRB approved study report that, through the use of participation incentives, 89% of the eligible cases agreed to participate and 60% of the 1060 controls approached agreed to participate. When you evaluate this paper you, Question 5 options: are concerned about non-response bias among the controls. are concerned about the ethics of using incentives. keep reading to insure there was no interviewer bias. are pretty impressed at the high rates of participation