Bayesian Hierarchical Framework from Expert Elicitation in the South African Coal Mining Industry for Compliance Testing

Felix Made; Ngianga-Bakwin Kandala; Derk Brouwer

doi:10.3390/ijerph20032496

Bayesian Hierarchical Framework from Expert Elicitation in the South African Coal Mining Industry for Compliance Testing

Int J Environ Res Public Health. 2023 Jan 31;20(3):2496. doi: 10.3390/ijerph20032496.

Authors

Felix Made^{1

2}, Ngianga-Bakwin Kandala^{1

3

4}, Derk Brouwer¹

Affiliations

¹ School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa.
² Global Biostatistics and Programming, Pharmaceutical Product Development, Part of Thermofisher Scientific, Woodmead, Johannesburg 2191, South Africa.
³ Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, ON N6G 2M1, Canada.
⁴ Département de la Santé Communautaire, Institut Supérieur des Techniques Médicales de Kinshasa, Kinshasa XI, Mont Ngafula, Kinshasa B.P. 774, Democratic Republic of the Congo.

Abstract

Occupational exposure assessment is important in preventing occupational coal worker's diseases. Methods have been proposed to assess compliance with exposure limits which aim to protect workers from developing diseases. A Bayesian framework with informative prior distribution obtained from historical or expert judgements has been highly recommended for compliance testing. The compliance testing is assessed against the occupational exposure limits (OEL) and categorization of the exposure, ranging from very highly controlled to very poorly controlled exposure groups. This study used a Bayesian framework from historical and expert elicitation data to compare the posterior probabilities of the 95th percentile (P95) of the coal dust exposures to improve compliance assessment and decision-making. A total of 10 job titles were included in this study. Bayesian framework with Markov chain Monte Carlo (MCMC) simulation was used to draw a full posterior probability of finding a job title to an exposure category. A modified IDEA ("Investigate", "Discuss", "Estimate", and "Aggregate") technique was used to conduct expert elicitation. The experts were asked to give their subjective probabilities of finding coal dust exposure of a job title in each of the exposure categories. Sensitivity analysis was done for parameter space to check for misclassification of exposures. There were more than 98% probabilities of the P95 exposure being found in the poorly controlled exposure group when using expert judgments. Historical data and non-informative prior tend to show a lower probability of finding the P95 in higher exposure categories in some titles unlike expert judgments. Expert judgements tend to show some similarity in findings with historical data. We recommend the use of expert judgements in occupational risk assessment as prior information before a decision is made on current exposure when historical data are unavailable or scarce.

Keywords: expert elicitation; expert judgments; exposure control categories; historical data; the 95th percentile.

MeSH terms

Bayes Theorem
Coal
Coal Mining*
Dust / analysis
Humans
Occupational Diseases*
Occupational Exposure*
South Africa

Substances

Coal
Dust

Grants and funding

This research received no external funding.