Assessing the accuracy of interviewed recall for rare, highly seasonal events: The case of wildlife consumption in Madagascar

Read the Commentaries on this Feature Paper: Unusual data in conservation science: searching for validation; Wildlife consumption and recall accuracy - but is it recall of hunting, of cooking or of eating? Response from the authors: Practical directions for the use of recall data in conservation science Researchers and practitioners from a range of fields including conservation biology, sociology, public health and economics rely on information gained from interviews to quantify the frequency and scale of activities or events of interest. These 'recall' data often form the basis of wildlife sustainability assessments and, ultimately, policy decisions and management actions, but they are highly vulnerable to bias, particularly when the behavior of interest has strong temporal variation. Here, we investigate bias in recalls of wildlife consumption in rural Madagascar by comparing oral recalls collected monthly and annually from male heads of household with daily diet diaries maintained by female heads of household. Daily diet calendars collected from 28 households were assumed to be the measure of true consumption and were used to validate the recalled information. While we found little interhousehold variation in accuracy of responses, we found a tendency for recalls to overreport rates of wildlife consumption. Estimating the annual frequency of rare and/or seasonal events was quantified more accurately by recalls of the prior year than by extrapolation of recalls of the prior month. We conclude that monthly variation in consumption rate leads to predictable errors in estimation of the annual consumption rate. Local consumption of wildlife has large temporal variability, reflecting human preference or the underlying life cycles of animals being consumed. Accurate assessment of consumption rates therefore requires determining an appropriate recall period by taking into account the temporal variability and frequency of the events in question. © 2013 The Zoological Society of London.