Fishbone diagram
Overview
- Causes can be classified into direct causes, contributing causes and root causes (see Types of causes in 5 Whys analysis).
- We advise that you use the Fishbone diagram as a visual tool to systematically brainstorm and organize potential direct causes only, based on different categories.
- For example, in GembaCI RCA the categories are:
- People: Refers to the workforce involved in the process, including
- operators,
- supervisors,
- engineers,
- and management.
Issues can arise from lack of training, insufficient staffing, poor communication, or human error.
- Process: Represents the sequence of steps or activities that convert inputs into outputs. Problems in this category may include
- unclear procedures,
- poor process design,
- bottlenecks,
- or inconsistencies in how the process is followed.
- Equipment: Involves the tools, machines, and technology used in the production process. Common issues might include
- equipment breakdowns,
- improper maintenance,
- outdated machinery,
- or incorrect tool settings.
- Environment: Encompasses the physical and operational conditions in which the process is carried out. This includes factors like
- lighting,
- temperature,
- humidity,
- noise levels,
- cleanliness,
- or even regulatory constraints.
- Measurement: Refers to the methods and tools used to assess performance and quality. Measurement problems could include
- inaccurate instruments,
- poor calibration,
- unreliable data,
- or ineffective monitoring systems.
- Material: Involves the raw materials, components, and consumables used in manufacturing. Issues can include
- poor material quality,
- inconsistent supply,
- contamination,
- or incorrect material selection for the process.
Steps
- Use the categories to brainstorm potential direct causes within each category based on the information you gathered in the Background. Ask for each category if there is any event or condition which may have caused the problem. Keep on asking what else could have caused the problem to identify all the potential direct causes in a category before you move on to the next category.
- When you are done with all the categories, identify the probable or most likely direct causes for the 5 Why Analysis from all the potential direct causes you have listed.
- Use the 5 Why Analysis to create the contributing causes and root causes.
