A Structured Expert Judgment Study for a Model of Campylobacter Transmission During Broiler‐Chicken Processing

Abstract

A structured expert judgment study was organized to obtain input data for a microbial risk-assessment model describing the transmission of campylobacter during broiler-chicken processing in the Netherlands. More specially, the expert study was aimed at quantifying the uncertainty on input parameters of this model and focused on the contamination of broiler-chicken carcasses with campylobacter during processing. Following the protocol for structured expert judgment studies, expert assessments were elicited individually through subjective probability distribution functions. The classical model was used to aggregate the individual experts' distributions in order to obtain a single combined distribution per variable. Three different weighting schemes were applied, including equal weighting and performance-based weighting with and without optimalization of the combined distributions. The individual experts' weights were based on their performance on the seed variables. Results of the various weighting schemes are presented in terms of performance, robustness, and combined distributions of the seed variables and some of the query variables. All three weighting schemes had adequate performance, with the optimized combined distributions significantly outperforming both the equal weight and the nonoptimized combined distributions. Hence, this weighting scheme, having adequate robustness, was chosen for further processing of the results.

Multi-Criteria Decision Analysis Tools for Prioritising Emerging or Re-Emerging Infectious Diseases Associated with Climate Change in Canada

“…Experts were from academic, government and independent backgrounds and were defined as individuals whose past or present field contains the subject under study i.e. infectious disease epidemiology and/or climate change, following [32], [33]. They were identified through literature and internet searching and via recommendations from other experts as described by the authors [9].…”

Ranking the Disease Burden of 14 Pathogens in Food Sources in the United States Using Attribution Data from Outbreak Investigations and Expert Elicitation

“…Expert elicitation is a set of formal research methods used to characterize uncertainty about existing scientific knowledge and to provide alternative parameter estimates when there are meaningful gaps in available data (7,31,38). Several studies have included expert elicitation to gain greater insight into attribution to food sources and other transmission pathways (9,18,44,55). As part of our larger research effort, Hoffmann et al (21)(22)(23) conducted an expert elicitation for attribution estimates on 12 of the 14 pathogens included in this study.…”

The use of expert elicitation in environmental health impact assessment: a seven step procedure

“…Parameters are also the most common subject of expert elicitations, and many examples in the environmental health literature exist. In the Campylobacter-elicitation [36], experts were asked to estimate several in- and output variables of a broiler-chicken processing model. From these estimates, the actual model parameters could be derived using probabilistic inversion techniques [38].…”

“…We illustrate the seven step procedure for formal expert elicitation using examples from three existing expert elicitation studies in the field of environmental health research: one on ultrafine particle exposure [34], one on genetically modified crops [35] and one on Campylobacter transmission [36]. The case-studies were chosen because they differ on the three main issues mentioned above and, hence, used different designs.…”