Problems With Six Sigma

While Six Sigma is a powerful tool, it does have some drawbacks and it is not suitable for every situation.

Six Sigma is a statistics-based measurement and analytical process that is intended to reduce defects to 3.4 per million opportunities. However, not everything in a business can be reduced to numbers. For example, improving customer experience would be very difficult with Six Sigma. It would also be difficult to use in capital goods sales, in which building relationships is important. Six Sigma would typically not be appropriate in marketing, consulting and service organizations in which people skills are valuable. Six Sigma is process focused, it is not customer focused.

There is also the opportunity for the numbers to be fudged in Six Sigma. With a target of 3.4 defects per million opportunities we first have to ask, "What is an opportunity?" We also need to ask, "What is a defect?" For example, a part of the process may be causing defects, but that part of the process is beyond the control of the Six Sigma team. The answer might be to set the definition of "defect" such that it does not include defects resulting from things that can not be controlled. The problem is, the customer still sees these as defects.

Plus there are two Six Sigma calculations - long term and short term. The long-term Six Sigma calculation includes a fudge factor that accounts for changes that occur over time, such as tool wear. However, not all processes change over time.

Another potential problem is that Six Sigma requires significant training. You can not move ahead with Six Sigma without having a staff trained in Six Sigma. Those with the highest level of training are called Six Sigma Black Belts. However, the training does not ensure the ability to apply Six Sigma in a practical way. And the training does not ensure the holder of a Black Belt has successful, practical experience applying Six Sigma. In other words the head knowledge may not translate into doing.

The bottom line is that Six Sigma is a powerful tool. But it is a tool that needs to be used correctly and applied to the right problems.