<P> PDCA (plan--do--check--act or plan--do--check--adjust) is an iterative four - step management method used in business for the control and continual improvement of processes and products . It is also known as the Deming circle / cycle / wheel, the Shewhart cycle, the control circle / cycle, or plan--do--study--act (PDSA). Another version of this PDCA cycle is OPDCA . The added "O" stands for observation or as some versions say: "Observe the current condition ." This emphasis on observation and current condition has currency with the literature on lean manufacturing and the Toyota Production System . The PDCA cycle, with Ishikawa's changes, can be traced back to S. Mizuno of the Tokyo Institute of Technology in 1959 . </P> <Table> <Tr> <Td> </Td> <Td> This section contains instructions, advice, or how - to content . The purpose of Wikipedia is to present facts, not to train . Please help improve this article either by rewriting the how - to content or by moving it to Wikiversity, Wikibooks or Wikivoyage . (October 2017) </Td> </Tr> </Table>

What are the four steps of a continuous improvement quality life cycle
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