When studying sensitive issues including
corruption, prejudice, and sexual behavior, researchers have
increasingly relied upon indirect questioning techniques to mitigate
such known problems of direct survey questions as under-reporting
and nonresponse. However, there have been surprisingly few
empirical validation studies of these indirect techniques, because
the information required to verify the resulting estimates is often
difficult to access. This paper reports findings from the first
comprehensive validation study of indirect methods. We estimate
whether people voted for an anti-abortion referendum held during the
2011 Mississippi General Election using direct questioning and three
popular indirect methods: list experiment, endorsement experiment,
and randomized response. We then validate these estimates against
the official election outcome. While direct questioning leads to
significant under-estimation of sensitive votes against the
referendum, these survey techniques yield estimates much closer to
the actual vote count, with endorsement experiment and randomized
response yielding least bias. |