Which tool is commonly used for root cause analysis in Lean?

The fishbone diagram, also known as the Ishikawa diagram, is a widely used tool for root cause analysis in Lean practices. This diagram helps teams identify and visually organize the potential causes of a problem, allowing them to trace these causes back to their root. By delineating various categories of causes, such as people, processes, materials, and environment, it fosters a comprehensive understanding of the problem instead of merely addressing symptoms.

The structure of the fishbone diagram encourages collaboration among team members, enhancing discussions around the potential factors contributing to an issue. This collaborative approach aligns well with Lean methodologies, which emphasize continuous improvement and the elimination of waste by addressing foundational problems rather than superficial ones.

In contrast, the other options focus on different areas of analysis. SWOT analysis is primarily used for strategic planning, assessing strengths, weaknesses, opportunities, and threats related to a business or project. Market trend analysis looks specifically at trends within a market to guide marketing and business strategy, while budget variance reports assess financial discrepancies rather than investigating root causes of operational issues. Thus, the fishbone diagram stands out as the most relevant tool for root cause analysis within the context of Lean practices.