Supply chain processes consist of interconnected stages such as planning, procurement, warehousing, and distribution. Any delay or misalignment occurring at one of these stages can directly affect operational performance. Therefore, issues in the supply chain should be evaluated not in isolation, but by considering the relationships between processes as a whole.
Lean Six Sigma is one of the methodological approaches that supports this perspective. Combining the Lean approach, which focuses on inefficiencies in process flow, with Six Sigma principles that analyze variability in process performance enables supply chain processes to be examined from both structural and performance-oriented perspectives. This makes it possible to analyze not only which steps make up a process, but also how these steps produce results over time.
What Is Lean?
Lean focuses on identifying activities that do not directly add value for the customer. In the context of the supply chain, these activities may include holding excess inventory, repeatedly moving products within the warehouse, delays during order approval stages, or heavy reliance on manual controls. Lean practices make visible where process flows slow down or are interrupted. This visibility supports clearer process analysis and helps identify areas for improvement.
What Is Six Sigma?
Once the process flow is clarified through Lean, the focus shifts to how this flow performs over time. Six Sigma uses data- and statistics-based methods to examine variability in process performance. In supply chain processes, issues such as delivery delays, incorrect shipments, or quality deviations are analyzed through measurable indicators. This analysis enables a clearer understanding of why processes produce inconsistent outcomes.
The Importance of the Lean and Six Sigma Approach in the Supply Chain
When Lean and Six Sigma are applied together, supply chain processes are evaluated not solely through individual indicators such as speed or cost, but based on whether processes progress in a stable and consistent manner. Lean highlights where waiting, repetition, and unnecessary activities occur along the order-to-delivery flow. Six Sigma, on the other hand, analyzes the frequency of deviations at these stages and how they relate to operational outcomes through data.
Within this framework, imbalances in inventory levels, delivery delays, and in-process errors are addressed not as isolated problems, but as issues linked to overall process execution. Especially in environments working with multiple suppliers, this approach enables clearer visibility into interactions between processes.
How Is Lean Six Sigma Applied in the Supply Chain?
Lean Six Sigma implementation begins with evaluating supply chain processes end to end as an integrated whole. During this assessment, stages such as order management, procurement, warehousing, and shipment are examined in terms of their roles and impact within the process, and measurement criteria are defined. Subsequently, non-value-adding activities and areas where performance deviations are concentrated are analyzed.
For example, if deliveries on a specific distribution route are consistently delayed, Lean makes visible waiting points such as multiple departments approving the same information before shipment. Six Sigma then analyzes how frequently these approval steps cause delays and how much they extend the overall process, using data-based insights.
Conclusion: A Structured Supply Chain with Lean and Six Sigma
When Lean and Six Sigma are applied together, a clearer view of how supply chain processes operate can be achieved. It becomes easier to monitor where process flows slow down, where recurring deviations occur, and how these deviations impact operational outcomes. This allows problems to be evaluated based on their roles within the process rather than as isolated incidents.
While Lean focuses on understanding process flow, Six Sigma enables analysis of how this flow performs over time. Their combined use supports examining supply chain processes from both structural and performance perspectives. Regular review of processes and monitoring performance deviations help organizations manage operations in a more controlled and consistent manner.
