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The first thing you should do is to recognize your part in the problem and take responsibility. An employer did not like what I had to say but he could not prove to himself or me that the problem was really those so-called “dumb employees” my hidden agenda is to stop employers from blaming innocent employees, I have seen many large plants and businesses in rural and suburban India doing massive layoffs that they could have avoided by using Six Sigma. It is sickening to watch the devastation that does not have to occur.

How to avoid the control phase: You cannot skip or get around the control phase of (Final Phase in DMAIC of Six Sigma) unless you eliminate the defect. The Main method used in the control phase are Statistical Process control (SPC).

You must ask the right questions to ensure control given below are some questions

1. What is your plan to enforce policy and procedures
2. What chart will be used to show how the process is working and ensure control of the solution?
3. Who is responsible for maintaining the solutions and control plans?
4. What are the consequences when the process is out of control?
5. Who will document and implement the monitoring plan?
6. What will be the standardized process?
7. What is the plan to share the knowledge gained on the process so it is institutionalized?
8. What is the review plan to maintain gain?

Statistical process Control (SPC)

SPC was developed by Walter Shewart in 1974. SPC is statistical based graphing technique that compares current process data with a set of stable control limits established from normal process variation. When data pints go beyond those control limits or when certain patterns appear between the limits, a process is said to be out of control.

As mentioned before , the six sigma approach often says that Y is a function of X, in Short , Y = f(X), to represent the idea that any output is a function of some input factors (X’s) and some X’s are the vital few variables.

There are many benefits to using statistical process control

• (SPC) groups data into patterns that can be statistically tested and provides insight about the behaviour of products or process characteristics.
• (SPC) facilities the understanding of the underlying cause system of products and process characteristics.
• SPC provides a graphical representation of product or process performance
• SPC detects assignable causes that affect the central tendency, and /or the variability of the sources from variation and defects.

The main use of SPC is that it serves as a decision making tool based on probabilities, acts as a practical tool for detecting changes in product or process performance in relation to historical performance ,or specified standards allows decision to be made based on sample data and point out when action is needed.

Overview of the Control Phase:

Here are some basic steps in the control phase using the standard steps for SPC to serve as a guideline for working with control charts.

1. Select the variable to chart
2. Select the type of control Chart to use.
3. Determine rational subgroup size and sampling interval / Frequency.
4. Determine measurement methods and criteria.
5. Calculate the parameters of the control chart.
6. Develop a control plan.
7. Train the people and use the charts
8. Conduct a phase-gate review.

The final step in the Control phase is to train the necessary people to implement and analyse the control charts.

To Conclude I would like to say when a process is in control it only means that the performance is stable and predictable, it does not mean that the performance is acceptable to customers. Now that we have discussed all the phases of DMAIC we will proceed to DMADV part of Six Sigma in my next article.

The author Suresh .V. Menon is trainer on Six Sigma and has worked in various capacities as Project Manager,ERP Consultant, Implementation Manager, Principal Consultant(QA) and can be contacted at testconsultants@outlook.com.