Identifying and closing the gap between the current and desired situation during a Lean transformation or any other process improvement effort. 

In a Lean management system, everyone is involved in problem solving. Two characteristics are leading here: 

1. Everything described or asserted during the problem-solving process (the problem itself; the desired situation, the immediate cause, the root cause) must be based on verifiable facts, not assumptions or interpretations. The fact that the burden of proof is on the problem solver is reflected in questions such as "How do you know? Did you go to the gemba first and get first-hand knowledge of the current situation? How do you know there is agreement on your improvement plan?'
   
2. Everyone recognizes that problem solving is a process
   that is never finished, which begins rather than ends with the implementation of an improvement plan. A plan is a theory of what will eliminate the cause of the problem, as well as what it will take to implement a countermeasure to that cause. The implementation process is a learning process to figure out what it will actually take to take steps toward the desired situation.
   

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