The overall aim of the research presented in this thesis was to examine the notification decision, the decision made by child protection workers that reported concerns relating to a child warranted a child protection investigation. This decision is critical in the process of child protection as it determines the entry of a child into the child protection process. The current state of knowledge concerning what constitutes child maltreatment, what causes people to maltreat their children and what the consequences of this maltreatment are to the children provides no definitive answers for child protection workers concerning what information is important when making decisions. The research presented in this thesis presents decision making based on two approaches -- mathematical modelling and the process of decision making based on cognitive processes. Research data for this thesis was collected by staff from the Queensland Department of Family Services and Aboriginal and Islander Affairs.