Statistical Thinking

Without any clearer understanding of Statistical Thinking, which is the philosophical background of 6 Sigma Activity, it could be a very difficult work to have it as the common language in the organization (company).
Today, I will talk about the definition and understanding of Statistical Thinking.
In Glossary and Table for Statistical Quality Control issued by ASQ (American Society for Quality) in 1996 in the U.S.,

It defines Statistical Thinking as;

Statistical Thinking is the philosophy related to study and management based on the three principles.
1) All work occurs in a system of interconnected processes.
2) Variation exists in all process.
3) Understanding and Reducing variation are keys to success.

We do general works inside the organization.  But now we need to change our thinking that work equals process, instead of working itself.  If we change work as process, 5 factors of process, so-called SIPOC should be considered accordingly.  The first step of improvement activity is to clarify what SIPOC are.

Here we simply explain to you about 5 factors in process.
Actually the internal process of organization (company) is one system connected from each department to customer.

Let’s take an example.
There are 3 internal processes in some company; R&D, production and promotion.  We have external suppliers, mainly contractors, and end-users who are our customers.  In each internal process, there is always the customer. In other words, customers are divided into internal and external one.  Once internal customers satisfy with us, it influences to external ones automatically. Each of them has their needs and wants. When we can fulfill what they need and want, it could be a perfect system then.

All processes provide customers with output all the time.   However, the problem is that output is changing, not fixed. We call it variation.  The second step is to accept there is variation in Output. This variation does not occur in Output but in supplier, input or process.

Now we understand there is variation in process all the time. This could be a cause of customer dissatisfaction as well.
For variation, we will handle in detail in the chapter of understanding Variation?

Therefore, the core innovation activity is to reduce Variation to provide customers with a stable output.  For this, we should optimize all processes.  A famous Doctor Deming even mentioned Variation is an evil?  Recently, we respect the diversity of individuals in the company to emphasize the creativity.  If the variation occurs from the diversity, it could be another problem.  So we should consider variety with Variation?