Statistical process control

statistical process control

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

An advantage of SPC is the focus on detecting errors early and preventing problems, rather than correcting problems as they occur.

In addition to reducing errors and quality costs, SPC will increase productivity because it is less likely that the finished product will need to be reworked or scrapped.

An SPC chart is designed like a Run Chart with control limits that distinguish normal and special variation. It is important to distinguish normal and special variation because they require different approaches when reducing variation.

Here's an example: Let's say that scrap at a manufacturing company arise from special cause variation; you can look for a specific cause (perform a root cause analysis). If scrap is due to normal variation, it is not possible to identify one special cause; the variation is part of the natural variation of the process. Normal variation is the result of random / natural variation of all variables that affect the process.

All processes have variation!

If a machine produces scrap because the normal variation is too wide, you have several options:

  1. You can invest in a machine that is more precise.
  2. You can choose to keep the machine and include the expected scrap cost in the product calculation to get the right price for the product.
  3. You can change the process to make the normal variation of the machine acceptable.

It is important to determine normal variation of machines to prevent spending time reducing variation that can not be reduced. It doesn't help to tune and adjust a machine that has too high normal variation. All machines have natural variation depending on how it is designed and mounted; By tuning and adjusting a machine with undesired normal variation it's likely to worsen the situation. Here is a video about application of statistical process control:


Other examples of SPC applications are:

  • Preventative Maintenance: Equipment wear will gradually increase variation. SPC will reveal increased variation of measurements and notify maintenance needs. An example is O-rings used for testing capillaries at a pharmaceutical company: When an O-ring starts to wear, it results in greater variation in the measurements. SPC can decide when it is time to change the O-ring. Dirty equipment can also cause greater variation of the measurements, indicating that it's time to clean! Operators with SPC knowledge can identify measurements that can predict maintenance need. 
  • Determining Capability: Is the process able to deliver on the customer's requirements?
  • Assessing Stability: is the process predictable and stable over time?
  • Compare machines and equipment for continuous improvement and to make the right decision when making new investments
  • Evaluate the effect of improvement work: has the average and / or variation changed?

Practical information

The course is arranged on request from companies with 6-15 participants. Courses can be tailored to your business needs, and your own data can be used in examples and assignments. 

Open courses are arranged according to the course calendar. 

Online course & online course with coaching can be started whenever you want. 

Lunch, refreshments and drinks during classroom training are included, and you receive a course certificate upon completion.


Classroom training is organized at the locations Lean Tech disposes at Lillestrøm (Svelleveien 33). Good access to parking spaces. It's 2 km from Lillestrøm train station.

Lean Tech has an agreement with Thon hotels and can set up courses elsewhere if needed. It is also possible to arrange business courses at the Company's location.


Instructor Sissel Pedersen Lundeby is IASSC (International association for Six Sigma certification) accredited trainer associate (only-one in Norway per August 2019):

"This accreditation publically reflects that you have met the standards established by IASSC such that those who participate in a training program led by you can expect to receive an acceptable level of knowledge transfer consistent with the Lean Six Sigma belt Bodies of Knowledge as established by IASSC."

Sissel has a Master in Chemical Engineering from NTNU (Norwegian University of Science and Technology) and 20 year's experience within manufacturing and environmental technology. In 2002 she started working at a US company where she was introduced to Six Sigma and completed her Black Belt certification. In 2017, she was also certified Black Belt through IASSC.

Sissel has positive experience using Lean Six Sigma to improve and focuses on measurable results. The courses use practical, recognizable examples and communicate Lean Six Sigma in a way that is easy to understand.


"Inspiring, professionally competent, popularize a theoretical discipline"

Espen Fjeld, Commercial Director at Berendsen

"Academic highly skilled and clear performance. Fun and builds trust"

Jon Sørensen, Production Manager at Berendsen

"10/10 good at reaching everyone"

Erlend Stene, Sales leader at Berendsen

"Clear and well presented. Good at asking questions and listen (check understanding)"

Morten Bodding, Production Manager at Berendsen

"Made a difference, engaged and skilled" - Participant from EWOS

"You are inspiring, positive and professionally skilled" - Participant from EWOS

Anonymous feedback:

"Clear presentations and well explained"

"I thought it was very rich, with good examples that made me reflect"


  • daryl powell"I was very impressed with Sissel's Lean Six Sigma knowledge. She makes it easy to identify improvements and create results"
    - Daryl Powell, Research Manager, Sintef ManufacturingValue stream mapping
  • eivindwilloch.original"Sissel has proven herself as a competent and committed employee. She has been an important contributor to make good progress in the projects she has worked with. At the same time she is accurate and has good quality of the work she performs."
    - Eivind Willoch, Project Manager, Cambi AS lean engineering
  • benchmarking"We are very happy with the work carried out. We was not very clear what the order was, but with your background and expertise the outcome was what we were looking for and a document we will benefit from in the future"
    - Roger Søråsdekkan, Site Leader at Allnex, Norwaybenchmarking
  • kjelleven rez"We hired Lean Tech to develop monitoring program for air emission. The assignment was delivered with the correct content at the right time. Recommended." monitoring program
    - Kjell Even Misfjord, SHE manager at Allnex, Norway  
  • rsz 1thomasløvik"Sissels ability to quickly understand the issue, as well as her commitment and expertise is impressive. Her analytical and thorough contribution to our monitoring program has been precise and targeted, and very educational. " monitoring program
    - Thomas Løvik, HSEQ advisor at TWMA, Norway
  • Joakim Holm Hansen"Very nice and professional service. Delivered a good job within deadlines" verdistrømsanalyse
    - Joakim Holm-Hansen, Plant Manager at Solenis, Norway
  • Feedback from course participants:
    "Inspiring, professionally competent, popularize a theoretical discipline."
    "Made a difference, engaged and skilled."
    "Academic highly skilled and clear performance. Fun and builds trust."
    lean six sigma kurs