This paper examines the SSM technique CATWOE, which focuses on defining necessary elements that together constitute a human activity system from a certain perspective. Despite its recognition within the literature and its numerous uses, there are few studies on how the technique can be improved. This research reflects on each of the elements both from a theoretical and a practical perspective. Findings point to the fact that some of the terms have a meaning in everyday language that differs from its definition within CATWOE. Other concepts are not well-defined. This is unfortunate and may both lead to misunderstandings and limit analysis. The paper points to a number of ways in which the use of CATWOE can be developed in order to further support the process of eliciting novel ideas for future actions. Hence, the overall conclusion is that the elements need to be rethought and some of them renamed.