A participant in the IRB Forum raised a question about a research study
where people were asked to participate, and when some of them said "no" they
were then asked why they did not want to participate. The reasons were
tallied across all of the refusals, and percentages were published as part of
the full research study. Since the people had already said "no" to
participating in the research study, did that also imply that they did not
want to share information about their reasons for not participating?
This is a difficult area, and most of the other comments in the IRB Forum
have been very critical. In contrast to those comments, I'd like to defend
this practice. The authors are trying to examine the extent to which
volunteer bias might influence the results of the research. This is an
important, but often neglected, issue in research. Almost every research
study requires informed consent. The major exceptions are certain
retrospective studies, certain studies in an emergency situation, and studies
involving a relatively benign intervention like prayer.
Those people who offer consent to participate almost certainly differ from
those who refuse. One example that I recall from my earlier work at the
National Institute for Occupational Safety and Health involved workplace
studies of reproductive toxicants. When you go into a workplace where there
is exposure to a chemical that might make men sterile, you usually don't have
trouble recruiting volunteers. Even with those people who are unconcerned
about their ability to reproduce, they usually end up volunteering to help
out their co-workers.
But the control group is a different story. There is no strong incentive to
participate, because the chemical being studied is not a problem at the place
where you work. So you have to worry about volunteer bias.
It turns out that one of the benefits for participation is getting a
complete reproductive health assessment. Now the sort of person who views
this as an incentive might be someone who was wondering "Hmm, my wife and I
have been trying to have children for the past six months and it just isn't
working." If those are the sorts of people who volunteer in greater numbers
in the control group, you will end up with a very bad bias in your
research. Not all of the couples who have been trying for six months will
have problems, of course, but enough might to seriously skew the control
group.
So in these reproductive studies, we would always ask people for the reason
that they decided to participate (was it for the money? to help out your
co-workers? to get a free exam?) and if possible, we would ask the people who
refused as well why they declined to participate. I never did those surveys,
but as I recall, if someone refused to participate, we would ask them if they
would mind filling out a half page questionnaire about their reasons for not
participating. If the participants differ from the refusals on these
questions, especially if the pattern of reasons is different between the
control group refusals and the exposed group refusals, you have learned
something very valuable about volunteer bias and about the limitations on
generalizing the results of this research.
It seems pretty obvious to me that some of the people would object to all
of the time and trouble required to participate in a full reproductive
assessment might not object to answering three questions on a survey.
So if someone refused to participate in a research study, I do not see a
problem with asking them "why" as long as the researcher is not rude or
pushy. They always have the option of saying "none of your business" but the
ones who do agree to offer reasons help us to better assess the scientific
validity of the study.
Now, it is unclear if the research situation cited above showed adequate
respect for the patients' right to be left alone, but I know that if you are
careful, you can query refusals without violating their rights.
This web page was written and was last modified on
09/24/2007.
