Modelling the effects of employee injury risks on injury, productivity and production quality using system dynamics

The aim of the current study is to explore the use of system dynamics (SD) modelling as a tool to examine the impacts of human factors in production on worker low back injury, productivity and quality performance parameters. The SD model was created using relationships in the scientific literature. This data supplemented with input from both a quality and a safety manager in an automotive plant, who also reviewed the resulting causal loop diagrams. Results showed that, over the 5-year simulation period of the base model, percentage of operators reporting low back pain increased from ∼0% to 1.3%, human error rates increased by 40%, and production rate dropped by 0.2%. This example model addressed three risk factors for a single injury type – and is therefore an underestimate of total system impacts of poor HF. While the extension of the model is needed, the current example highlights a cautionary point for managers and designers who may not see an immediate impact of a poor design but may face increased injury, quality and productivity problems over time. This novel application of SD modelling can help isolate and quantify these effects.