
85Potline Process Control Failure
◻ Yes ◻ No
• Has there been a change in policies or procedures, e.g., maintenance
procedures?
◻ Yes ◻ No
• Is the process adjusted frequently?
◻ Yes ◻ No
• Did the samples come from different parts of the process? Shifts?
Individuals?
◻ Yes ◻ No
• Are employees afraid to report “bad news”?
Note: A team should address each “yes” answer as a potential source of a special cause.
References
1. Stone, R., and M. Taylor. 1995. Time series models in statistical process control:
Considerations of applicability. The Statistician 44 (2): 227–234.
2. Taylor, M. P., W. D. Zhang, V. Willis, and S. Schmid. 1996. A dynamic ...