A novel integrated Six Sigma and simulation approach for reducing waiting time in emergency departments

Abstract

Long waiting times in emergency departments remain a critical challenge for healthcare systems. This study proposes an integrated framework combining the DMAIC (Define, Measure, Analyze, Improve, Control) methodology with simulation-based analysis to improve outpatient waiting times. In the Define phase, a SIPOC diagram was used to clarify processes and stakeholders. Key causes of delays were identified in the Measure phase using a Fishbone Diagram, while the Analysis phase applied FMEA to prioritise improvement actions. In the Improve phase, agent-based simulation was developed to model patient behaviour and process interactions, estimating patient flows across emergency department pathways. These outputs informed a discrete-event simulation model used to evaluate alternative operational scenarios for reducing waiting times. Finally, in the Control phase, statistical analysis was conducted to assess sustainability. A Wilcoxon test confirmed that the reduction in waiting times was statistically significant, demonstrating the effectiveness and stability of the proposed improvements.