Fishbone Diagram: A better choice for Six Sigma Root Cause Analysis

The Six Sigma approach is a process for the structured analysis of data. It requires that a project be put through a process which consists of Define, Measure, Analyze, Improve and Control. In the Measure phase, a key tool called the "Fishbone diagram" is used to review the problem by explaining the collection of variables or root cause of a problem. The Analyze phase requires a lot of inputs from many experts and it usually runs in parallel with measurement.

During the Analysis stage, ascertain the problem precisely and patiently work thorough all the potential factors. In the beginning, make sure to identify and record the inputs for the problem. These inputs may be perceptible, unlikely or difficult to define. Keep nothing out of the scope during the initial analysis stage by leaving no stones unturned. Employ brainstorming techniques to come up with an array of factors. Some of these facts may be instinctive and obvious, while others might require the support of investigation, data and review.

As a part of improving products and services, the group must enlist all the inputs of experts and their full participation with emphasis in their different departments and processes.

As identification of inputs occurs, the fishbone diagram develops as a result. While the look of the diagram should not be the focus, capturing all inputs is crucial. As an input is identified, additional causes could be identified. Each of these inputs and causes begin to branch from the larger bones. Throughout the process, identification may go several levels deep, which results in the shape. Each root cause is a small bone. If additional causes affect an input, it is not considered root. When working with a manufacturing environment, the following categories are frequently used:

1. Measurement - identify the source causes and defects under that scope. Measuring devices from the six sigma approach are also included.

2. Man - one among the main categories when working in a manufacturing environment. Though other categories also contribute to the inputs to the system, man is potentially. The main source of these inputs would be from brainstorming sessions and conversations.

3. Machines - the sources of the effects of machines within the work environment are included. To detect whether a particular machine or several machines are creating the defect is beneficial to identify the sources of the problem.

4. Method - This step involves enabling the transparency of the processes in a system. This transparency will help in detecting problems and defects in the initial stages.

5. Material is one of the categories considered when working with a manufacturing environment. May it be the raw material or any piece involved in the manufacturing process, it should undergo a quality survey initially. Any defects in them can be a reason for failure in the end of the manufacturing process. If corrected initially the final outcome will be proper.

6. Environment - Aspects of the work area may also be a cause for poor quality. Environmental reasons should be looked into to rule out their role for any harmful effects.