Assessing the accuracy of interviewed recall for rare, highly seasonal events: the case of wildlife consumption in Madagascar C. D. Golden 1 , R. W. Wrangham 2 & J. S. Brashares 3 1 Center for the Environment, Harvard University, Cambridge, MA, USA 2 Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA 3 Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA Keywords oral recall; food frequency; illegal activities; wildlife; hunting; accuracy assessment; bias; bushmeat. Correspondence Christopher Golden, Center for the Environment, Harvard University, 24 Oxford Street, 3rd Floor, Cambridge, MA 02138, USA Email: cgolden@fas.harvard.edu Editor: Nathalie Pettorelli Associate Editor: Ioan Fazey Received 10 October 2012; accepted 28 March 2013 doi:10.1111/acv.12047 Abstract 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 vulner- able to bias, particularly when the behavior of interest has strong temporal vari- ation. 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 house- hold. 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. Introduction The use of data derived from a subject’s recall of specific events from memory is a central component of many studies in conservation science, sociology, economics and public health (Coughlin, 1990; Eisenhower, Mathiowetz & Morganstein, 1991; Gavin & Anderson, 2005; Brigham et al., 2008; Ellsberg et al., 2008; Jones et al., 2008). Activi- ties, behaviors and events that are difficult for researchers to directly observe often require the use of recall methodolo- gies to estimate frequencies, durations and/or periodicity of occurrence. Policymakers depend on the reliability of these data to inform their decisions regarding household econom- ics, human health and environmental sustainability. In many cases, researchers estimate event frequencies by extrapolating from recall information based on a small sample of prior days or weeks (Eisenhower et al., 1991; Lemmens & Knibbe, 1993). Such an approach assumes (1) that a subject can accurately recall the events of interest, (2) that the events quantified during a brief recall period remain roughly constant in frequency throughout the year and (3) that the timing of the recall period will capture or detect events of research interest (Lemmens & Knibbe, 1993). However, these assumptions are often violated such that estimates based on extrapolation from short recall periods are vulnerable to systematic and response errors (Lemmens & Knibbe, 1993; Johansson et al., 2002). This problem can be further compounded by investigators designing surveys to be conducted during periods where events of particular interest will occur relatively frequently. Assessing the accu- racy and precision of these recalled estimates by using mixed-method data collection is needed to determine the validity of researcher’s reliance on this form of inference (Rosenberg et al., 1983). In this study, we use a case of hunting and wildlife con- sumption in north-eastern Madagascar to assess the accu- racy of annual recalls for rare and seasonal events. Prior evidence has shown that hunting in this region is highly seasonal, and for some species, rare (Golden, 2009; Golden et al., 2011). We compared prior month with prior year Animal Conservation. Print ISSN 1367-9430 Animal Conservation •• (2013) ••–•• © 2013 The Zoological Society of London 1