Seven Basic Tools of Quality

"A root cause is an initiating cause of a causal chain which leads to an outcome or effect of interest. Commonly, root cause is used to describe the depth in the causal chain where an intervention could reasonably be implemented to change performance and prevent an undesirable outcome." [Root cause. Wikipedia]
"Problem-solving consists of using generic or ad hoc methods, in an orderly manner, for finding solutions to problems. Some of the problem-solving techniques developed and used in artificial intelligence, computer science, engineering, mathematics, medicine, etc. are related to mental problem-solving techniques studied in psychology." [Problem solving. Wikipedia]
This root cause analysis (RCA) tree diagram example "Personal problem solution" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Seven Management and Planning Tools solution from the Management area of ConceptDraw Solution Park.