Statistical Process Control (SPC) is used for quality control to ensure that the process produces within customer requirements.

With SPC you can detect errors early and prevent problems, rather than correct problems as they occur.

SPC also helps you to respond properly to measurement result and to address stability and capability.

I once had a summer job at “Sjømennenes Helsehjem”, and how to boil the eggs was a hot topic.

The residents were not always pleased with the boiled eggs. However, it was complicated to please them since some residents were very happy while others were dissatisfied, with eggs cooked exactly the same way.

"The devil is in the details"

Improving quality is about understanding and controlling variation.

Several variables influence a result. However, some variables are more important than others.

All measurements involve uncertainty.

Suppliers of measuring equipment usually specify the measurement uncertainty as a symmetrical interval around the measurement result:

Measurement result ± measurement uncertainty

Example: The length of a special measuring rod is 2000 mm ± 1 mm.

Variation can be positive in contexts like "varied workday," "varied training", etc.

For manufacturing companies variation can create headaches and huge cost.

When and how do you respond to a result?

Do you use facts or intuition? Do your customers decide when to react?

Or maybe you use statistical process control?

How do you react? Do you start looking for a special cause?

I have experienced operators adjusting a machine in despair because the machine produced rejects.

No matter how much they adjusted, the machine still produced rejects.

The adjustments did not help, in fact it resulted in more rejects.

The best way to find out is to test! You can do that at the Norwegian museum of Science and Technology.

I did an experimental design where I tested age, gender and sense (vision and hearing). My brother in law (35 years), my son (10 years), my niece (7 years) and I (41 years) were volunteers.

I am impressed by the flow at Espa Bolleland, a Norwegian gas station 90 km north of Oslo.

We often stop here, and we are not the only ones...

What's so amazing with Espa bolleland, is that besides all their visitors, you experience a good flow.