Page 146 - The Six Sigma Project Planner

Prepare an Audit Report
After receiving the response from the process owner, the audit team should prepare a
written audit report. The audit report should document the findings of the audit team,
including recommendations for remedial action, actions already taken or planned by
the process owner, the names of persons responsible for the action items, and deadlines
for completing each action items.
The audit follow-up plan can be considered a subproject. The report should first be
presented to the process owner and then revised if necessary. The final report should be
presented to the entire Six Sigma project team for approval. Upon approval by the team,
a summary report should be sent to the project sponsor. The Summary Audit Report, or
its location, should be included in the Appendix of the Planner in the Audit Report
section on p. 207.

Determine Sigma and DPMO Levels for CTx’s

Critical-to-quality characteristics are measured in terms of defects per million
opportunities. CTQs and DPMO criteria were established previously, in the Define
phase (p. 106). We will now analyze these metrics.
At this point in the Six Sigma project, data are collected and the exact quality levels
determined for all CTQ characteristics and for many CTC and CTS characteristics. This
information will help us with our move forward planning by telling us if the existing
business process has the potential to deliver quality levels that meet our project goals. It
also tells us what the process is actually delivering. By comparing these two values, we
can measure the actual-potential gap. Actual and potential performance must also be
compared with the best practices performance levels determined in the future state
description (p. 144).

Process Capability and Process Actual Sigma Levels for
Continuous CTx Characteristics
For CTx’s measured on a continuous scale, we will use calculated sigma levels to
measure process performance, e.g., a sigma level of 6 would indicate 3.4 PPM per-
formance. We call data obtained for CTx’s measured on a continuous scale variables data.

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Measuring Process Capability for Variables Data
Imagine a process operated in a state of perfect statistical control. For a variable CTx,
this state is operationalized when the X-bar and range or sigma charts indicate no
special causes for an extended period of time. In Six Sigma analysis, when this stable
state exists, the process capability is measured by using the process mean and standard
deviation and assuming a 1.5σ shift will take place in the long term. Process reject rates

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Note: Although capability indices (Cpk, etc.) are equivalent to Z-scores, we will not discuss process
capability indices here. For more information on relating Z statistics to these indices, see The Six Sigma
Handbook, Chapter 13.

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