6 Sigma - Chapter2

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© Copyright 2004, All Rights Reserved. Edutech Dimensions Pvt. Ltd.
Chapter 2: Process
Aim
This chapter focuses on processes, defines the three process analysis and process
control methods and describes one of them i.e., Performance statistics, in detail.
What is a process?
A process is a combination of machinery, materials, procedures and manpower that
are used to produce a product or deliver a service.
A process reveals information or data. Six Sigma methodology collects this data to
accurately assess the time, waste, defects or other variations associated with a
process. And this provides the information needed to improve the process itself.
Take for example, the customer complaint handling process. The quality of this
process could be quantified using certain parameters like the number of complaints
received, the response time for each complaint and reduced repetitiveness of the
same complaint. This is the data given out by the process. To enhance any of these
parameters, say to reduce the response cycle time, action needs to be taken over
the entire process. So the data from the process is used to improve the entire
process.
Key Characteristics
The features in a product or service that are most important to the user are called
the key characteristics of a product.
Typically, you would look at features that are most important to the customer and
call these the Key characteristics.
For example, while developing a software for the integration of databases and legacy
applications for a client, the emphasis would be on a bug free solution,
interoperability, stability and of course, on the client not losing any of his old
databases.
Statistical process control and capability measures should be applied to key
characteristics. Non-key characteristics are not unimportant. They will still receive
the same attention they have received traditionally.
By focusing on the Key characteristics, quality teams over time can analyze and
control most, if not all, of a company’s processes.

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© Copyright 2004, All Rights Reserved. Edutech Dimensions Pvt. Ltd.
Another way of looking at key characteristics is to use the loss function concept.
From this point of view, key characteristics are those whose variations cause the
greatest loss and would possess steep sided loss functions. This would indicate
significant potential losses owing to variation.
Flat loss function indicates low potential losses and represents non-key
characteristics.
Action on the Key Characteristic of the process
Actions on a process are most economical when taken on key-characteristics varying
far from target value. This maintains stability and variations within acceptable limits.
Action taken on output is not economical. Unless the root cause is removed, the
problem or non-conformance may appear once again.
Focusing on key characteristics provides a method to allocate quality resources in the
most effective manner
Summary
1. Any repetitive action constitutes a “process” and is a combination of
machinery, materials, procedures and so forth that are used to produce a
product or deliver a service.
2. Six Sigma methodology collects data to assess the time, waste, defects or
other variations associated with each process and uses these to improve the
process.
3. Key characteristics reflect manufacturing situations where there is a high
probability of a defect occurring or going undetected should it occur.
4. Six Sigma focuses on key characteristics and reduces the chance of defects to
a large extent.