What is the PDCA Cycle and how is it relevant to ISO Certification and ISO Standards?

A statistician, Dr. Walter A. Shewhart used his skills, statistics to explain the process variability. It was him who first developed this concept of PDSA cycle (Plan – DO – Study – Act). Dr. W. Edward Deming who publicized the usefulness of his mentor’s work including the Shewhart Cycle.

Deming was trained as a mathematician, and he applied his mathematical concepts and tools (Statistical Process Control) to reduce variation and prevent defects. He then went onto become one of the leaders in Quality.

Deming improvised on Shewhart’s cycle and re-introduced Deming Wheel (PDCA) in later stage of 20th Century in 1993 and called it as PDSA Cycle.

He emphasized on a fact that ‘Check’ phase in PDCA cycle is focussed on evaluating the change in terms of its results whether the plan was a success or a failure and find needed corrective actions to succeed in case of failure.

His objective to replace ‘Check’ step with ‘Study’ phase was to stress on analysis of the steps taken and results obtained, then to evaluate them and come up with the possible revised solutions to attain desired results.

This approach is a repetitive or iterative process for planning and executing ‘change activities’ for continuous evaluation and improvement.

What is the PDCA Cycle

The steps involved in Deming PDCA or PDSA (Plan-Do-Study-Act) Cycle as shown are as follows:

  1. Plan a change (P).
  2. Do it (D). Carry out the change, suggested on a small scale or as prototype.
  3. Check it (C). Observe the effects of the change. Study it (S).
  4. Act on what was learnt (A).
  5. Repeat the same process from Step 1 with new insights and continuously evaluate and improve.

PDCA is not a concept that it looks easy to understand but, if interested in ISO Management Systems standard then it is evident that a PDCA cycle is a solid foundation and greatly beneficial. Better understanding of PDCA cycle makes it easier for implementing and getting ISO Certification of any standards.

What is the PDCA Cycle

How is PDCA cycle relevant in ISO?

ISO Standards that are developed off late are based on a high-level structure that has 10 clauses which all ISO management system standards are required to follow that framed around the PDCA cycle. This is so needed that all standards developed will have the same look and feel and will enable easy integration with various ISO standards.

As a structured ISO standard, the requirements defined in the form of clauses are as per PDCA concepts and for an ISO system to work effectively, focus has to be given on each PDCA element equally and not just focus on few areas like Plan, Do) and neglect the other two elements of PDCA (Check, Act).

In ISO 9001 standard, the concept of Process Approach is detailed on how important it is to implement an International Management System Standard that is compliant with requirements. The methodology known as “Plan-Do-Check-Act” is being used and applied to all processes across the standard requirements. This then gives the relation of the overview of how the standard requirements get aligned within a PDCA cycle.

The goal of any international management system standard developed by ISO is to work towards the improvement of a company. Any organization that thrive grow in the industry would want to improve their processes internally to be able to compete in the market. With the help of PDCA cycle, any organization will be to focus on the processes and objectives of the ISO Standard and its overall expected improvement, which further leads to savings in time and money that can be used to improve further and deliver quality products and services. The focus on quality on the processes followed to deliver the end results would largely differentiate between the organizations that outperform their counterparts. To understand better about the scope quality and its influence across the organization, please do refer this blog on total quality management.


We can look at each PDCA element and how ISO Standard clauses aligns with Plan Do Check Act.


Any business should have a planning cycle that chalkout the plans which includes stakeholders, organization values, objectives and policies, aspects of budget, resources and related documented information.

These are the high-level planning elements.

Maintain QMS (4.1, 4.2 & 4.3)

Leadership (5)

Planning (6.1, 6.2, 6.3)

Manage Resources (7.1)

Document QMS (7.5)



This is the actual execution phase of whatever has been planned based on the objectives set by management. This activity/ task generates various facets of data and records on a regular basis as the plans are being transformed/ executed into a reality. These data that are generated in tandem with the process of execution, are used for measurement and analysis as a result of execution as per plans initiated. The junk of execution is focused/ evolved around clause 8, Product Realization. Most of the documented information is around clause 8.

Competence (7.2)

Design, Develop, Realize (8)

Purchasing (8.4)

Product & Service Provisions (8.5)



Once we have the data or records generated through “Do” phase, this must be analysed or studied (Deming’s PDSA cycle – Study).

As discussed before, the focus of Deming was to give impetus on analysis and study of the data generated from ‘Do’ phase rather than just to check if the execution was a success or failure of what was planned.

Alignment of ISO standard with PDCA cycle defines a way to check processes internally in order to identify how well an organization has been executing the plans as defined.

Monitor & Measuring (9.1)

Customer Satisfaction (9.1.2)

Data Analysis (9.1.3)

Internal Auditing (9.2)

Management Reviews (9.3)

The processes that are defined in the form of ISO standard is not a one-time activity but has to be performed on a repeated basis on a regular interval till the desired results are achieved.



This phase is all about the actions taken to close the issues/ gaps that are identified during the ‘Check’ phase where the actual measurement and analysis of deviation from plan vs records evident during execution.  There is also a need for management to take steps as part of ‘Act’ in the areas like management review. Theis step involves action plans set by management to either as a corrective measure to overcome the failures in the process or as a step taken to prevent further deviations.

Risk Management (6.3)

Nonconforming Product (8.7)

Corrective Action (10.2)

This same Plan Do Check Act cycle is being used in various phases of standard like training, documentation, support activities, etc. The whole concept of continuous improvement relies on PDCA cycle and the ease of implementation of ISO standards largely depend on how effectively has PDCA cycle played its role in aligning the business objectives and processes to ISO standard requirements.

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