1. 1. 2010 Colt Technology Services Group Limited. All rights reserved. For internal use only Introduction to Process Control The What and the Why Author: Ray McGlew
2. 2. Managing by the Monthly Report Managing a company by means of the monthly report is like trying to drive a car by watching the central line in the rear-view mirror Myron Tribus
3. 3. Limitations of Typical Monthly Reports Retrospective & delayed data Difficult to interpret Impossible to explore relationships between data elements Difficult to understand variation
4. 4. Variation Exists In Every Process Process Results Every process shows variation in performance due to a combination of factors People Offices Equipment Environment Process/Procedures Systems/Applications
5. 5. What is Process Control? Process Control is the routine activity of monitoring a process to identify when action should be taken and what type of action is required The type of action required depends on whether the process is broken or unbroken
6. 6. Unbroken Process Exhibits only natural variation Is stable and results are predictable, based on the laws of probability However, the process may not be capable of consistently delivering the required results Variation predictable A Process that is unbroken:
7. 7. Broken Process Exhibits unnatural variation Is unstable and results are unpredictable A Process that is broken: Variation?
8. 8. What is natural and unnatural variation?
9. 9. Natural Variation Also referred to as Random or Common Cause variation Occurs due to the design & management of the process itself Pointless trying to determine the cause of individual data points Requires Management intervention to instigate process analysis to identify and remove causes
10. 10. Unnatural Variation Also referred to as Attributable or Special Cause variation Occurs due to specific circumstances These data points must be investigated immediately they occur These can normally be resolved by the people operating the process themselves, but not always
11. 11. How Do We Determine What To Do? If a process is broken If a process is capable of meeting its customers requirements The type of action required to improve the performance of a process The gains achieved by process improvement action Use Process Control Charts to enable you to determine...
12. 12. What is a Process Control Chart? It is a time plot that indicates the range of variation built into the process The boundaries of this variation are marked by Upper and Lower Control Limits (UCL & LCL) These control limits.. are calculated according to statistical formulas, using data collected on the process enable you to quickly identify signals of unnatural variation are not related to targets or budgets, they only indicate what the process is capable of achieving
13. 13. Parts of a Control Chart Upper Control Limit (UCL) Lower Control Limit (LCL) Average Control Limits are calculated as 3 standard deviations from the average 302520151050 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
14. 14. Basic Parts of a Process Control Chart 302520151050 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 The vertical axis is the unit of measurement e.g. Days to Deliver The horizontal axis represents time e.g. Week Number (data must be plotted in time order) The scale allows for the level of variation inherent in the process
15. 15. Basic Parts of a Process Control Chart A centre line is calculated as the average of the data points collected 302520151050 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Average
16. 16. Basic Parts of a Control Chart Upper Control Limit (UCL) Lower Control Limit (LCL) Average Control Limits are calculated as 3 standard deviations from the average
17. 17. Basic Parts of a Control Chart Upper Control Limit (UCL) Lower Control Limit (LCL) Average Warning Levels are calculated as 1 and 2 standard deviations from the average Zone A Zone B Zone C Zone A Zone B Zone C
18. 18. Signals of Variation How do you determine if the variation is natural or unnatural? Look for the following signals
19. 19. Natural Variation Data points fall randomly between the upper and lower control limits and either side of the average line UCL LCL Average
20. 20. Signals of Unnatural Variation UCL LCL Data point falls outside the upper or lower control limit Average These must be investigated as soon as they occur
21. 21. Signals of Unnatural Variation UCL LCL 8 consecutive data points above or below the average line Average
22. 22. Signals of Unnatural Variation UCL LCL Average 8 consecutive data points rising or falling
23. 23. Zone A Zone B Zone C Zone A Zone B Zone C Signals of Unnatural Variation UCL LCL Average 4 out of 5 consecutive data points within Zones B and C
24. 24. Signals of Unnatural Variation UCL LCL Average 2 out of 3 consecutive data points within Zone C Zone A Zone B Zone C Zone A Zone B Zone C
25. 25. Process Targets Targets for performance are determined by the expectations of customers or business differentiators Process Control Charts determine the actual level of performance a process is capable of achieving Process Control Charts help to determine the gap between target performance and actual performance
26. 26. How to Identify Gaps in Performance The following slides show how Process Control Charts are used to determine if there is a gap between the performance its customers require it to deliver and the performance the process is capable of delivering The first step would normally be to identify the needs of the customers of the process referred to as Voice of the Customer
27. 27. Voice of the Customer 302520151050 Process OutputsInputs Voice of the Customer Days to Deliver For this process, customers have defined their expectation of service as no more than 10 days to deliver
28. 28. Voice of the Process Voice of the Customer Customer expects 10 days Process delivers between 5-25 days, average 15 days UCL needs to be reduced to 10 days, gap is 15 days Process is out of control Remove special causes first, then reduce common causes Gap 302520151050 Days to Deliver Voice of the Process
29. 29. Voice of the Process Voice of the Customer 302520151050 Days to Deliver Voice of the Process Gap Process improved UCL reduced to 18 days Average to 10 days Gap now 8 days Further improvement required
30. 30. Voice of the Process Voice of the Customer 302520151050 Days to Deliver Voice of the Process Process improved UCL reduced to 10 days Target time can be guaranteed
31. 31. Voice of the Process Voice of the Customer 302520151050 Days to Deliver Voice of the Process UCL reduced to 5 days Best of Breed Competitive advantage
32. 32. Key Messages Variation exists in every process Management are accountable for reducing the variation inherent in a process they have to instigate process improvement activities Staff are responsible for investigating the variation that occurs in a process Process Control Charts enable you to determine the level of natural and unnatural variation within a process Process Control Charts enable you to determine the gap between actual performance and target performance
33. 33. Interpreting the Control Chart Most of the points will occur near the average line Few points will be near the upper and lower control limits Rarely will a point fall beyond the control limits The points should appear as a random distribution on the chart, without cycles or trends As long as the process is operating under a stable system, you can expect: