What is Statistical Process Control (SPC)?

Statistical Process Control (SPC) was first developed in 1920 and has since helped numerous organsiations radically improve their process efficiency, as well as help ensure quality products and services are consistently delivered.  

From multinationals like Motorola, General Electric, and Toyota, to National Healthcare organisations like the NHS, SPC has revolutionised the way businesses interpret and analyse their data. Giving decision-makers a definitive point of reference to base business-critical decisions.  

In this article, a general understanding of SPC will be covered, followed by a brief look at its history and where SPC is today.  

What is SPC?

SPC can be understood as a philosophy, a strategy, and a set of analytical tools for improving the efficiency of processes and systems. The American Society of Quality (ASQ) defines SPC as “the use of statistical techniques to control a process or production method. SPC tools and procedures can help you monitor process behavior, discover issues in internal systems, and find solutions for production issues”.  

In other words, SPC is a set of analytical techniques which involve plotting data overtime on charts, helping businesses understand normal versus abnormal variations in their data, which they can use as a guide to take the most appropriate action.  

SPC is a powerful tool for monitoring and predicting process performance, as well as identifying areas of improvement, and monitoring the sustainability and success of actions on those improvements.  

History of SPC:

SPC was first developed by physicist Walter A. Shewhart whilst working for Bell Labs, an industrial research and scientific development company. Founded in Shewhart’s theory of variation (differentiating between common and special causes of variations in data), Shewhart was the first to create the ‘control chart’ as a methodology to determine whether a process was in a state of statistical control, hence the term, Statistical Process Control.

Control charts were designed to help identify deviations and abnormalities in the recording of data, such as very high or low observation. Since then, the SPC ecosystem has expanded to include several different chart types that can be used for a variety of business operations.

A notable example of a historical use of SPC was in the Second World War, where the United States used SPC to ensure the quality of munitions and other important military products. Whilst its use dropped after the war, SPC technique’s use grew in popularity in the 1980s and has steadily been adopted by businesses in a range of different industries across the globe.

SPC Today:

All businesses today, regardless of the specific industry have seen increased competition, rising operational costs, and rising costs of production. To have tools at a business’s disposal that enhance the control and efficiency over business operations and processes is therefore key to remaining competitive.  

Today, the main objective in utilising SPC is enabling the continuous improvement of processes using data analytics and statistics to analyse data and process information, thus giving decision-makers the information they need to take the most appropriate action. This is where SPC is key; it gives businesses the ability to take the most unwavering course of action, by harnessing their data and using it as a definitive point of reference.  

Unlike other quality control methods which work by correcting issues after they have occurred, i.e. process inspection, SPC enables businesses to detect and prevent problems prior to them occurring.

Whilst SPC is commonly associated with the manufacturing and healthcare industry (the NHS’s adoption of SPC has produced some impressive results), the scope for SPC is not limited to any one specific industry.

In summary, any organisation or business which has measurable processes can benefit from adopting SPC charts.  

For more information on Statistical Process Control please get in contact with one of our specialists by emailing us at, info@bcn.co.uk or calling us on, 0345 095 7000.