Child maltreatment is an important problem. High quality decision-making is crucial to determine whether child abuse or neglect occurs. This dissertation aims to gain insight into the factors which influence the decision-making of professionals in child welfare and child protection and which could improve decision-making in cases of (suspected) child maltreatment. Therefore, research was conducted on: 1) the effects of structured decision-making on the quality of judgments and decisions (the so-called ORBA method); 2) the effects of the use of a risk assessment instrument (LIRIK) on the agreement and predictive validity of risk estimations; 3) how professionals reason about the intervention recommendations. The effects of the structured decision-making method and the risk assessment instrument both appear to be limited. They support professionals in considering more relevant case factors. However, their use did not increase agreement on judgments in child maltreatment cases. Furthermore, professionals’ decision-making was substantially influenced by their personal reasoning and attitudes regarding child abuse and out-of-home placement. This finding provides a potential explanation for the limited effects of the use of ORBA and LIRIK we found: such methods and instruments do not seem to counteract personal attitudes and reasoning. Therefore, it is necessary to find additional ways to improve decision-making, besides the use of tools such as ORBA and LIRIK. This may include, among other things, so-called ‘critical thinking’ (systematically considering – potentially in teams – alternative explanations, purposefully generating arguments and counterarguments for the interventions proposed and for alternative interventions) and more often shared decision-making with parents and children.