Introduction:
If the project involves an improvement to existing systems, the term “control” is used to refer to the final six sigma project phase in which tentative recommendations are confirmed and institutionalized.
Verify phase:
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This follows because inspection controls are being put in place to confirm that the changes do initially increase quality and that they continue to do so. If the associated project involves new product or service design, this phase also involves confirmation. Since there is less emphasis on evaluating a process on an on-going basis.
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The term “verify” refers evaluation on a one-time, off-line basis. Clearly, there is a chance that the recommended changes will not be found to be an improvement.
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In that case, it might make sense to return to the analyze and/or improvement phases to generate new recommendations. Alternatively, it might be time to terminate the project and ensure that no harm has been done.
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In general, casual reversal of the DMAIC or DMADV ordering of activities might conflict with the dogma of six sigma. Still, this can constitute the most advisable course of action.
Control planning:
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The method of “control planning” refers to a coordinated effort to guarantee that steady state charting activities will be sufficient to monitor processes and provide some degree of safeguard on the quality of system outputs.
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Control planning could itself involve the construction of gauge R&R method applications and statistical process control charting procedures.
Acceptance sampling:
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The method of “acceptance sampling” provides an economical way to evaluate the acceptability of characteristics that might otherwise go UN inspected .Both acceptance sampling and control planning could therefore be a part of a control or verification process.
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Overall, the primary goal of the control or verify phase is to provide strong evidence that the project targets from the charter have been achieved. Therefore, the settings should be thoroughly tested through weeks of running in production, if appropriate.
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Control planning and acceptance sampling can be useful in this process. Ultimately, any type of strong evidence confirming the positive effects of the project recommendations will likely be acceptable. With the considerable expense associated with many six sigma projects, the achievement of measurable benefits of new system inputs is likely. However, a conceivable, useful role of the control or verify phases is to determine that no recommended changes are beneficial and the associated system inputs should not be changed.
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Finally, the documentation of any confirmed input setting changes in the corporate standard operating procedures (SOPs) is generally required for successful project completion. This chapter begins with descriptions of control planning and acceptance sampling methods. It concludes with brief comments about appropriate documentation of project results.
