The results of applying Soft Systems Methodology (SSM) show that the nature of the solution and improvement in the problem situation involves some ambiguity. This is due to SSM’s theoretical inadequacy in extending multiple conceptual models to an agreed-upon human activity system. In fact, one of the most important and controversial issues in soft operations research is to ensure how the solution has been obtained and to secure whether the conditions under which the solution has been obtained were satisfied. This (...) article presents the necessary and sufficient conditions for achieving human activity systems as a solution to one of the widely-used methodologies of soft operations research, i.e. Soft Systems Methodology. Similarly, with the aim of reaching a better understanding of the nature of the solution provided by SSM, the soft solution is compared through an example with that of hard systems methodology. (shrink)