The focus of this thesis is on social workers’ knowledge in assessing and making decisions in child welfare cases. The primary aim is to identify what skills or knowledge social workers find most useful within child welfare agencies in Swedish municipalities. Six different types of knowledge, social policy and the approach of child welfare cases are perspectives considered in the analysis. The interviews with social workers were held in three agencies in southern Sweden, in 2014. Main results: social workers’ think it is very important to have different kinds of knowledge and skills in order to perform such professional work as possible. They value peer support where they can exchange experiences and knowledge with each other. The importance to specialize after the bachelor’s degree in social work was also revealed in the results, due to the social work supplementary course only represented undergraduate studies. The approach of child welfare cases it was found that there are many different ways to manage them, but the main thing is to manage the cases with great respect and always strive to apply volunteer efforts where it’s possible. Another point is the political importance which we not counted on.

The study is about how social workers perceive their power to be partly expressed and partly handled in the meeting with guardians in advance assessments in child welfare cases. The data collection was done through eight semi-structured interviews, which were done with a question guide. The question guide was designed so that we could answer our study´s questions. The analysis was done using a qualitative content analysis. As a theoretical framework we used Foucault's theory regarding power. The results of the study showed that the power expresses itself by sending summons to guardians. But also through the law and the guardian's fear of social workers' knowledge, as well as due to the guardian's ignorance regarding advance assessments. The results of the study also showed that social workers manage power by helping the guardian create trust in the social worker, motivating the guardian. Social workers also manage power by explaining the situation, listening, changing the focus and being clear through, for example, threats about their power to open a childcare investigation.