Purpose
The Cause and Effect diagram, also known as a Fishbone diagram, is a useful tool to organize your observations gathered during a current state analysis. Observational groupings help the team generate and validate their root cause hypothesis.
Filling out a Cause and Effect Diagram
The "head" of the diagram contains your project's problem statement and your observations are organized along one of six "bones": Measurements, Material, Machines, Environment, Methods, and People. These categories are meant to help group observations; you can change the name of the "bones" to categories that resonate more with your team. Themes and root causes emerge as you complete the diagram.
NOTE: When documenting your observations, it is more important to add observations on the Cause and Effect diagram than to worry about documenting them on the correct bone
There are two forces in current state analysis- the flare and focus phases. During the flare phase of your analysis you will document all your learnings collected during your gemba walks and interviews. The intention is to explore all options that are potentially causing the problem. The same observation may present itself numerous times from different sources, which is an indicator of an emerging theme. The next step requires Focus, or a narrowing of attention to determine why the observation is presenting itself.
5 Whys
You are encouraged to deep deeper during the focus phase by using the 5 Whys technique. By continuing to ask Why? you drill down to the underlying root cause of a symptom. On the cause and effect diagram, this is visualized by smaller "bones" branching off of "larger" bones.
