PDCA (plan, do, check, act)

PDCA was named for the first time in the 30`s by Walter Shewhart, who discussed about this concept in his book “Statistical Method from the Viewpoint of Quality Control”.
PDCA cycle have connections and is pretty the same as other problem solving methodologies, simple or more complex, like 8D, DMAIC from Six Sigma. Even recent changes to ISO 9001 process-based orientation chapter came with new concept risk-based thinking - closely linked with the PDCA.