Problem Solving is a term that is often used to describe any form of improvement activity. The term is also used more precisely to define the process of investigating the causes of why things are not working as expected, so that root causes may be identified and eliminated.
It is important to recognise that improvement covers more than Problem Solving, so that we should not be satisfied with a process simply because it is working as expected. We should also be looking for improvements beyond the current level of performance.