This tool is most effective when used in a team or group setting.
1) Use a white board, butcher-block paper, or a flip chart to get started. You may choose to use "Post-it" notes to move causes around as you decide on categories.
2) Write the problem to be solved (the EFFECT) as descriptively as possible on one side of the work space, then draw the "backbone of the fish"
3) The next step is to decide how to categorize the causes. There are two basic methods: A) by function, or B) by process sequence. The most frequent approach is to categorize by function. In manufacturing settings the categories are often: Machine, Method, Materials, Measurement, People, and Environment. In service settings, Machine and Method are often replaced by Policies (high level decision rules), and Procedures (specific tasks). In this case, we will use the manufacturing functions as a starting point, less Measurement because there was no variability experienced from measurements. You can also use process steps as bone for brainstorming.
4) You can see that this is not enough detail to identify specific root causes. There are usually many contributors to a problem, so an effective Fishbone Diagram will have many potential causes listed in categories and sub-categories.
5) The usefulness of a Fishbone Diagram is dependent upon the level of development - moving past symptoms to the true root cause, and quantifying the relationship between the Primary Root Causes and the Effect. You can take the analysis to a deeper level by using Regression Analysis to quantify correlation, and Designed Experiments to quantify causation.
6) After creating your chart on a flip-chart or white board, you can replicate it using most processing programs or spreadsheets (Microsoft Excel,Minitab).
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