PlanDoCheckActZyklen

The PlanDoCheckActZyklen, often abbreviated as PDCA cycle, is a four‑step method for continuous improvement of processes and products. It is based on learning from small experiments and cycles of planning, implementing, reviewing and acting. The concept originates from the work of Walter A. Shewhart and was popularized by W. Edwards Deming as a core tool of quality management.

The four phases are Plan, Do, Check and Act. In Plan, objectives are defined, a process or change is designed and metrics are chosen. In Do, the change is implemented on a small scale or in a pilot, and data are collected. In Check, the results are analyzed and compared with expectations to determine whether the change produced the desired effect. In Act, the organization decides whether to adopt the change, adjust it and run another cycle, or abandon it and revert to the prior state. If successful, the change is standardized.

PDCA is widely used in manufacturing and services and is integrated into quality management systems such as ISO 9001, as well as in Lean and Six Sigma projects. It is also used in software development and project management to promote iterative learning. In healthcare, a variant called PDSA (Plan-Do-Study-Act) is common.

Benefits include structured problem solving, risk reduction, and enhanced team learning. Limitations include the potential for superficial execution, misapplication as a mere checklist, and the need for clear goals and short cycle times.

PDCA remains a flexible framework for incremental improvement.