Do you really know what Shewhart Cycle is ? -Part 1-

The Shewhart Cycle -Part 1-

 PDCA – Plan, Do, Check, Act

Also Presented  as  “The Deming Wheel” or “The Shewhart Cycle” or “PDSA: Plan Do Study Act”

Background

PDCA’s were first described by Walter A Shewhart as Plan, Do and See in 1939 in his book, Statistical Method from the Viewpoint of Quality Control² which is rooted in the scientific method (Francis Bacon 1620). The scientific method can be written as "hypothesis"–"experiment"–"evaluation" or plan, do and check.  Shewhart’s protégé W. Edwards Deming modified the cycle to Plan, Do, Study, Act and put the concept to work.  Deming was an American Statistician who couldn’t get buy-in from his American counterparts in the post-war era.  Japan, however, welcomed him and he is associated with the invention of Total Quality Management (TQM) and the rise of Japan as a manufacturing nation.  In Japan, Deming taught about the use of statistics and the PDSA cycle. Within 50 years, attributable in part to Deming and his wealth of knowledge, Japan went from manufacturing cheap products to manufacturing some of the highest quality products in the world.  In 1960 Deming was given a medal by the Japanese Emperor for his service to the country’s industry.

PDSA Cycles are related to Kaizen thinking.  The term Kaizen is derived from two Japanese characters; kai, meaning “change” and zen meaning “continuous improvement.” Eliminating waste in the value stream is the goal of Kaizen. Alternatively, Six Sigma programs utilize the notion of PDSA cycles in their DMAIC strategy-"define, measure, analyze, improve, control".

Plan-do-check-act (PDCA cycle)

One method for implementing and sustaining continuous improvement involves a useful tool called the 'plan-do-check-act' cycle or PDCA.

The PDCA cycle may be used to implement improvements and to ensure that improvements are sustained in all critical areas of the business such as safety and environment, quality, morale, delivery and cost.

The environmental management system detailed in the ISO 14004:2004 International Standard follows a PDCA management model.

PDCA is an ongoing, iterative process that enables a business to establish, implement and maintain and continually improve its environmental policy.

The PDCA cycle is a checklist of four stages you must go through, from identifying the area for improvement through to the improved work area. It emphasises and demonstrates that improvement programs must do the following:

1.      Start with careful planning.

2.      Result in effective action.

3.      Check the results.

4.      Move on again to careful planning in a continuous cycle.

The four stages are illustrated in Figure 1.

Figure 1: The PDCA cycle

The plan stage is performed throughout the planning and implementation of improvement solutions.

During the check stage the team collects data and checks whether the solutions are producing the expected improvements.

During the act stage the team monitors the process to identify further improvement opportunities and takes action to introduce them.

However, the improvement process does not stop here. As continuous improvement is never-ending, the PDCA cycle continues. PDCA is what drives continuous improvement.

Here is a guideline to the plan-do-check-act cycles.

Plan

      Establish an ongoing planning process.

      Describe the results you want to achieve.

      Identify and monitor applicable legal requirements, policy objectives  and other commitments.

      Set internal performance criteria where appropriate (operating standards, timeframes, quality control, cost considerations).

      Clarify the standards (time, quality, cost etc).

      List all activities required to achieve the results.

      Prioritise the activities.

      Determine the timing and duration of each.

      Prepare a diagram to illustrate the activity sequence.

      Allocate people and resources.

      Set objectives and targets on what should be measured, where and when it should be measured and what methods should be used.

      Develop and use performance indicators.

Do

·         After the planning stage, the plan needs to be implemented.

·         Assign roles and responsibilities.

·         Maintain operational control and emergency response.

·         Provide all adequate resources including the implementation of document control.

·         Provide training to relevant staff.

·         Establish processes for internal communication.

Check

·         You need to evaluate and measure the results.

·         Complete a systematic approach to monitoring and measurement activities that ensure compliance by identifying the key characteristics through a process approach.

·         Progress is compared against key performance indicators and set targets from the planning stage.

·         Identify nonconformity and take corrective and preventive actions.

·         Manage records.

Act

·         Review and take action to improve the company's operations. Identify areas for improvement and make recommendations.

·         Here you need to improve the process further. For example, if results achieved are as planned against the targets set, the current method is captured in a new or revised standard operating procedure (SOP) to ensure future success.

·         When results are not as planned, the PDCA cycle is repeated on the same business activity with recommendations on what went wrong detailed for part of the next planning cycle.

·         An essential element of continuous improvement is aiming higher next time so that the review stage sets higher targets than previously recognised.

·         When results are successful the PDCA cycle is completed on another area of the company for continual improvement.

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