PDCA (Plan-Do-Check-Act) cycles are one of the most important parts of lean, because improvement is a cycle (learn more here).
I am often asked if all steps are really important or if the sequence truly matters. The short answer is YES. The long answer is YES, because:
- No “Plan” –> you are working without a goal. This creates useless tasks, repetitive and redundant testing and, even worse, nobody will really know if things are going ok or not. If you don’t have a goal, there is no standard definition of “good” or “success”. In other words, you don’t have a hypothesis. It is also difficult to have a motivated investigation team if they don’t have a clue of the goal of their work.
- No “Do” –> you might have great plans and a very clear goal, but you will not learn until you do experiments and prove/refute your hypothesis (learn more here). This problem usually happens with very complex issues, inexperienced people or high-risk situations (“I’m scared to try”). The effect is often called “paralysis by analysis”.
- No “Check” –> testing results are incompletely or not analyzed at all. Learning will not happen and/or conclusions will be wrong.
- No “Act” –> working standards are not updated. Knowledge is not incorporated to regular work and the company is condemned to repeat the same errors again and again.
As a summary: