Purpose: For many foodborne diseases included in the WHO Global Burden of Foodborne disease initiative, conventional observational data needed to estimates source attribution estimates was unavailable. The purpose of this study was to examine the feasibility of designing expert elicitation studies that could provide food source attribution estimates where globally comparable conventional data was unavailable.
Methods: The WHO committee commissions an expert elicitation using the Cooke classical method. This method has been applied broadly to develop parameter estimates for risk modeling where primary data is not available, but not in such a global setting. Preliminary research used review of literature, primary data, 1-on-1 interviews and pretests to evaluate alternative regionalization structures and calibration questions.
Results: The research identified a series of factors that were needed for regionalization schemes and mapped these to existing global regionalization schemes. GEMS regions were determined to be too geographically disperse and not to reflect factors other than consumption affecting source attribution. Experts involved in pretests found WHO regions too heterogeneous to be able to provide meaningful estimates. WHO sub-regions were determined to provide a balance between respondent burden and heterogeneity. Pretesting found experts were able to appropriately respond to calibration questions at the WHO sub-region level.
Significance: Preliminary design research showed that it was possible to develop an expert elicitation that could be used to in the GBD study to fill gaps in source attribution estimates.