PDCA Cycle Tool (Plan-Do-Check-Act)
Improve anything by running small experiments instead of big rewrites. The PDCA cycle (Plan, Do, Check, Act) from Deming is the engine behind kaizen, lean, ISO 9001 and most quality systems: state a hypothesis, run a small test, measure honestly, then standardise or revise. Track iterations to see what actually changed over time. Auto-saves in your browser, exports as SVG, PNG, JSON or text.
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How to use this pdca cycle tool
- Name the cycle with the process being improved + iteration (e.g. 'Onboarding flow — iteration 3'). PDCA is iterative; the counter exists to track that you're learning, not just running cycles.
- Plan: write a specific hypothesis with a measurable outcome. 'We think shortening the form will increase signup completion by 10%' is testable. 'Improve onboarding' is not.
- Do: run the change at small scope (one team, one segment, one week). The goal here is data, not full rollout — that comes later.
- Check: compare the actual data to your Plan target. Don't argue about whether the change felt good — let the numbers speak. Note surprises, especially negative ones.
- Act: roll out, roll back, or run another iteration with tweaks. Click 'Start next iteration' to bump the counter — that history matters when reviewing what you've actually learned.
Frequently asked questions
What is PDCA?
A continuous-improvement cycle — Plan, Do, Check, Act — popularised by W. Edwards Deming and built on Walter Shewhart's earlier work at Bell Labs. Used as the underlying engine in lean manufacturing, kaizen, ISO 9001, Six Sigma and most quality management systems. The core idea: improvement comes from many small validated experiments, not from one big rewrite.
How is PDCA different from PDSA?
PDSA (Plan-Do-Study-Act) is Deming's later refinement. He swapped 'Check' for 'Study' because Check sounds like checking a box for compliance, while Study emphasises learning — actually understanding why the result differed from prediction. PDSA is more common in healthcare improvement; PDCA dominates manufacturing and software. Same cycle, different emphasis on what the third step is for.
How long should a single PDCA cycle take?
Match the cycle to the risk and feedback loop of what you're changing. A small UI tweak: a sprint (1-2 weeks). A manufacturing process change: a month. An org-wide policy change: a quarter. The right rhythm is the shortest cycle that produces meaningful Check data — too fast and you measure noise; too slow and you forget why you ran the experiment.
Why does PDCA fail in most organisations?
Three failure modes: (1) people skip Plan and jump straight to Do — they're 'too busy' to write a hypothesis, then can't tell if the change worked; (2) Check is skipped because the result wasn't measured upfront; (3) Act never happens because the next 'urgent' thing arrives. The fix is uncomfortable: refuse to start Do without a measurable Plan, and put Act on the calendar before starting Do.
PDCA, Lean, Six Sigma — what's the relationship?
PDCA is the underlying loop. Lean uses PDCA continuously across many small kaizen events to eliminate waste. Six Sigma's DMAIC (Define-Measure-Analyse-Improve-Control) is essentially a more rigorous, statistics-heavy PDCA for variation reduction. ISO 9001 mandates PDCA as the basis of any quality management system. They're not competitors — they're different intensities of the same fundamental loop.