Summary
Highlights
The Fishbone Diagram, also known as the Cause and Effect Diagram or Ishikawa Diagram, is a method for identifying, exploring, and organizing contributing factors to a problem, aiming to uncover its actual root cause rather than just symptoms. Business analysts use it for root cause analysis, quality improvement, process improvement, risk anticipation, and solution specification.
The problem is the high-level issue or effect that needs understanding and is the central focus of the diagram. It originates from a well-formed problem statement and is typically represented as a large fish head on the right, emphasizing it as the single, largest item to address.
Cause categories are general groupings for the problem's causes. These can be derived using different methods: the 8 Ms (Manpower, Machines, Materials, Methods, Management, Measurement, Maintenance, Mother Nature) for manufacturing; the 8 Ps (Product, Place, People, Process, Promotion, Productivity, Price, Physical Evidence) for marketing and service industries; or the 4 Ss (Surroundings, Suppliers, Systems, Skills) for supply chain or retail, where external factors are crucial. Categories irrelevant to a specific problem can be omitted.
Sub-causes are potential issues contributing to the problem, grouped under cause categories. Primary causes are specific issues directly contributing to the problem, represented as large branches. Secondary causes explain how primary causes contribute to the problem, stemming from primary branches. Tertiary causes provide deeper insight into specific mechanisms of secondary causes, represented by the smallest lines and considered optional.
Creating a Fishbone Diagram involves defining the problem, gathering subject matter experts, drawing the diagram template, and determining appropriate cause categories (8 Ms, 8 Ps, or 4 Ss). Next, brainstorm possible primary, secondary, and tertiary causes within each category. After completing the cause and effect analysis, prioritize causes using methods like the Pareto principle (80/20 rule) and multivoting. Finally, perform a root cause analysis on prioritized causes using techniques like the 5 Whys, and create an action plan with corrective actions, assessment measures, and owners.
When creating a Fishbone Diagram, focus strictly on causes during brainstorming, not solutions. Distinguish between factual and belief-driven causes, validating beliefs later. Involve diverse, cross-functional teams for comprehensive insights. Prioritize causes to optimize root cause analysis efforts. Use clear and common language, avoid jargon, and maintain consistent symbols and colors. Most importantly, define a robust action plan with responsibilities and timelines for identified root causes.
A university admissions department exceeding SLA by two weeks is used as an example. The 6-Ps method is applied (omitting 'Physical Evidence' and 'Price'). Primary causes are brainstormed (e.g., 'Insufficient Staffing,' 'Manual Review'), then analyzed for secondary and tertiary causes. Prioritization using multivoting identifies 'Insufficient Staffing' and 'Manual Review' as most impactful. The 5 Whys technique reveals root causes like communication gaps between departments and executives.