The list experiment: Piloting a new method for measuring abortion in Liberia
Awarded 2013
Trainee Grants
Heidi Moseson Lidow, MPH
University of California, San Francisco

Background: Measurement of sensitive behaviors is often limited by high levels of underreporting due to stigma and concerns about privacy. Abortion in particular is notoriously difficult to measure. Validation studies in the US find that up to 70% of abortions are not reported via traditional surveys. This study implements a novel method to estimate the population experience of induced abortion in Liberia, where abortion is illegal, and often unsafe. Methods: In a randomly selected, population-based sample of 3,219 women ages 15-49 years in Liberia, we piloted the list experiment. Each woman was read two lists: a list of non-sensitive behaviors, and a list of correlated non-sensitive behaviors with abortion added. The sensitive item, abortion, was randomly added to either List A or List B for each respondent. The respondent reported a simple count of the options on each list that she had ever experienced, without indicating which options. Difference in means calculations between the average counts for each list were then averaged to provide an estimate of the population proportion that had an abortion. Results: The list experiment estimates that 32% (95%CI: 28-36) of respondents surveyed had ever had an abortion, with a 95% response rate. Results from a validation sub-study suggest that the list experiment succeeded in reducing under-reporting. Conclusions: The list experiment generated an estimate five times greater than the only previous representative estimate of abortion in Liberia (6%), and is consistent with anecdotal evidence, indicating the potential utility of this method to reduce underreporting of sensitive issues.