The growing shortage of skilled social workers, accompanied by an ageing population and the increasing number of fragile, elderly individuals that require social services, poses a serious challenge for our society. The magnitude of this problem is seen in the various predictions hypothesizing that, globally, there is likely to be a shortfall of millions of social workers for the successful provision of social services. To make matters worse, there are not enough social work students to fill that void, whereas the existing employee turnover is another serious concern for the social work field. Policy makers in many countries do not yet understand the pattern of growing needs and have no tool to forecast the future increase in educational requirements for creating a pool of adequately skilled social workers. In addition to this, understanding the patterns of workforce entrance and exit for social workers and the dynamics of transition becomes important for national policy and decision makers. In our paper, we build on current research about knowledge management in social work settings to demonstrate that knowledge management can have a positive impact in helping to fulfil the important role of social work in any ageing society. With our research, we contribute to the underdeveloped literature about knowledge management in the public sector and especially in social work settings and to the knowledge-based view of the organization. We present a multiple decrement model of social workers’ entrance and transition from social work student and social worker trainee to fully productive social worker, to their exit, whether by changed profession, retirement or death. We argue that the availability of social workers in a national economy depends on the development and operationalization of appropriate policies, where knowledge management can be influential. Our model allows measuring the quality of the national policy system related to the social work profession, something which has not been achieved yet, and shows how knowledge management solutions can positively influence the whole field of social work. We apply an objective measuring tool, grounded in an already developed actuarial–mathematical method. Our case relies on the collection and analysis of relevant data found in publicly available statistical reports for Slovenia. Existing data enables us to provide assumptions on how to better forecast the transition of social workers.