The document discusses the PDCA (Plan-Do-Check-Act) cycle, a four-step model for continuous improvement. [1] The PDCA cycle was developed in the 1930s and popularized by Dr. Edward Deming in the 1950s. [2] It is used as a tool to plan improvement, implement changes, observe the results, and determine what actions need to be taken. [3] The cycle helps create a culture of quality and allows businesses to continuously improve both internally and in response to external factors.