Not all business problems lend themselves to the Six Sigma process improvement methodologies, especially those that have short time lines. There are many problems that business leadership understand and should just fix. A Six Sigma improvement project typically requires one to six months for a team to complete, depending upon the complexity and scope of the problem. This is longer than acceptable for some problems. In addition, many of the tools used in Six Sigma do not apply well to problems that are not process based. Examples of these would be emergencies and relationship issues. Process improvement tools apply better to up-front planning for these situations, than to the situations themselves.

Two other important considerations are the impact of variation and the truth. Not all variation is bad. Without variation, there would be no improvement. Six Sigma projects use variation to find both problems and solutions. This is because the awareness of a better way to do something manifests itself as variation. Consider, for example, that there are two processes producing an identical output. The operator of one process makes a change and introduces variation between the two processes. This new process produces fewer defects than the former process. Thus, by way of introducing variation, the operator discovers a better way to produce the output. Conversely, by eliminating all variation, we eliminate all experimentation, and as a result, we eliminate process improvement. The key is to plan and control variation. By planning and experimenting, a process owner can discover new and better ways to produce the product or service.

The truth is the basis of any effort to improve processes and eliminate defects. Sacred cows, sub-optimization, and parochialism are enemies of the truth and place limits upon how much improvement is achievable. To optimize improvement, we must embrace the truth, even if it hurts. The truth will literally set us free.