PDCA/Deming cycle illustration (credits: [4,5])


The Plan-Do-Check-Act cycle or Plan-Do-Check-Adjust methodology (also known as Deming cycle or Shewart cycle) is an abstract iterative-incremental procedure model, defined to find a solution to a problem by continuously improving the status quo.


Imagine the wild allure of the Old West, as depicted in the 1988 film Young Guns. This era, characterized by lawlessness and the pursuit of a better life, presents a thrilling yet harsh reality. Similarly, today’s startup culture often embodies a bold, adventurous spirit, reminiscent of those times. Startups are fueled by passion and ambition, yet they frequently encounter the harsh realities of business, such as unforeseen expenses and the consequences of hasty decisions. This parallel underscores the need for a structured approach to business planning and quality management, which is where the Plan-Do-Check-Act (PDCA) cycle comes into play.

Plan-Do-Check-Act (PDCA) Cycle

The PDCA cycle, also known as the Deming cycle or Shewhart cycle, is an iterative and incremental method for problem-solving and quality improvement. Originating from the realms of manufacturing and business management, its principles are universally applicable, promoting continuous improvement across various domains, including software engineering and startup operations.

Historical Background

The PDCA cycle was initially conceptualized by Walter A. Shewhart, a pioneering American physicist, engineer, and statistician, in the late 1930s. Shewhart proposed a three-step process of “Specification, Production, Inspection” to enhance work quality systematically. This model was later expanded by W. Edwards Deming, who introduced an additional step (“Act/Adjust”) to emphasize the cycle’s continuous nature of improvement. Deming’s contributions popularized the methodology, leading to its widespread adoption in quality management systems.

The PDCA Phases

  1. Plan: This phase involves setting objectives and developing processes to achieve them. It requires a thorough analysis of the current situation and the identification of areas for improvement. For software projects, this translates to requirements analysis in collaboration with stakeholders.
  2. Do: Here, the planned solution is implemented on a small scale. This prototype or pilot project allows for testing the feasibility and effectiveness of the proposed changes.
  3. Check: In this phase, the results of the pilot implementation are evaluated against the objectives set in the planning phase. This evaluation helps identify any discrepancies and areas for improvement.
  4. Act (Adjust): Based on the feedback from the “Check” phase, necessary adjustments are made to refine the processes. This may involve revising goals, methods, or even the solution itself to better address the problem.


The PDCA cycle represents a foundational approach to problem-solving and continuous improvement. By iteratively refining processes and solutions, organizations can adapt to challenges more effectively and achieve sustained quality improvements. Just as in software development, where version control is a best practice, the iterative nature of the PDCA cycle encourages a structured approach to continuous enhancement.


  1. https://en.wikipedia.org/wiki/PDCA
  2. https://en.wikipedia.org/wiki/Walter_A._Shewhart
  3. https://de.wikipedia.org/wiki/William_Edwards_Deming
  4. https://slidehunter.com/powerpoint-templates/plan-do-check-act-powerpoint-template/
  5. https://creativecommons.org/licenses/by/4.0/