This method, named after H. Ishikawa, enables a simple recognition and analysis of causes and effects of a problem circle. Central problems become apparent, as well as the interactions of the cause complexes, furthermore the entire problem can be revised in a structured way. The persons involved are made to understand the problem together. Once the problem has been identified, a graphic is drawn up which uses arrows to assign the causes to their effects and thus to the problem. Since there are often several different reasons for a problem, the Ishikawa root cause analysis classifies them according to four influencing factors: Man, Machine, Material and Method. The following phases regulate the procedure in this technique: First, the problem is defined, then the main causes are determined. Then brainstorming takes place on the individual causes, the most probable of which are selected. Finally, after a review, one tries to find possible solutions. (Source: Gabler Management)