The Deming cycle: plan–do–check–act

Plan–do–check–act (PDCA), often called the Deming cycle, structures improvement as repeated experiments. A team plans a change and its expected result, carries it out, studies the evidence and then standardises, adapts or abandons the change before beginning the next cycle.

When to use it

Use PDCA to bring discipline to continuous improvement, problem-solving, training, objectives and control processes. The method distinguishes active management from repeated firefighting: each cycle makes the theory, action and learning explicit.

Teach the method to everyone expected to lead improvement. Visible results from small cycles build confidence and encourage further work, while the repeated loop prevents a successful change from becoming a one-off event.

Origins

The cycle grew from Walter A. Shewhart’s statistical approach to quality control, which treated specification, production and inspection as an iterative learning process. W. Edwards Deming taught and popularised that experimental logic in post-war Japan. Deming later preferred plan–do–study–act, because ‘study’ stresses learning from evidence rather than merely checking whether a task was completed.

What it is

How to use it

Work through every stage and keep the scale of the test proportionate to the uncertainty and risk.